Lakhasly

Research Problem Success at university level mainly depends on existing pre-entry university attributes, including the mastery of some fundamental academic skills (Tinto, 1993).Firth (1957) stated, "You shall know the word by the company it keeps" (p.11). The intended message of Firth's citation here is to classify words not only on the basis of their meanings, but also on the basis of their co-occurrence with other words. Word collocation includes the distribution of word uses and senses, comparing the use of synonymous words, and dictionary definitions. Investigating the use of synonymous distribution enables learners to determine the contextual preferences associated with other collocates (Firth, 1957). Nation (2001) provides a comprehensive framework of the information that is necessary to improve word use at different levels. The information consists of three components: form, meaning, and use. Each class encompasses three different aspects of knowing a word, in which he also split the knowledge of words into two types: receptive and productive knowledge. These components and sub-components are made to enable learners to differentiate their capabilities to receive language input through reading or listening and understand it. In addition, the aforementioned components help to distinguish the learners' ability to produce oral or written words in an appropriate context, utilizing the proper spelling and pronunciation. The 'form' aspect involves the written and spoken knowledge that learners should take into consideration when learning new words. The aspect of 'meaning' includes words' meanings, concepts, referents, and the association of words. The aspect of 'use' covers the grammatical functions of words, their collocations, and their use restrictions. The following table illustrates Nation's framework (2001) regarding vocabulary knowledge. Nation (2001) classified vocabulary knowledge into 18 questions grouped into three categories, in which each category contains receptive and productive aspects. The framework defines vocabulary knowledge from different perspectives: pragmatic, semantic, and morphological perspectives and it shows that all of the aspects are closely interrelated. For instance, the meaning of a word could be derived from the context or the form of that word (Gu, 2017). However, Nation realizes that this framework is incomplete and needs modification. He indicates the difficulty of measuring vocabulary knowledge by only using this classification. He also added that the aspects of this classification are interrelated with each other, which makes differentiating between certain words difficult. Vocabulary size refers to the amount of vocabulary needed to understand and use the language (Karakoc & Kose, 2017). Language learners need to expand their vocabulary size since "vocabulary is a continually changing entity with new words and new uses of old words being added and old words failing into disuse" (Nation & Waring, 1997, p. 6).Within the context of L2 research in reading, findings on the reading processes and vocabulary threshold have consistently indicated the importance of vocabulary knowledge in reading comprehension (Fukkink et al. 2005, Garcia 1991, Koda 1994, Laufer, 1997, Zhang 2000, 2002a, 2002b; see Alderson 2000, Bernhardt 2005, and Nation 2001, for reviews).Vocabulary Size Test: The VST provided a quantitative measure of the participants' vocabulary size so that the scores could be collated and subjected to statistical data analysis The Vocabulary Size Test employed in this study was originally developed by Nation (1983) and later it was amended and revised by Schmitt et al. (2001).For the study of human phenomena, qualitative researchers employ a variety of systems of inquiry, such as biography, case study, historical analysis, discourse analysis, ethnography, grounded theory, and phenomenology, as opposed to logical and statistical methods.This analysis helps in evaluating the quality and effectiveness of the reading comprehension assessment and the extent to which it promotes different levels of thinking .Content analysis is a research method used to systematically examine and categorize the content of text, including reading passages and comprehension questions.The selection of those words has also taken into consideration the words' universality (words are that are used across countries where English is the primary medium of communication), utility (words that cover a broad range of genres), and usefulness (words that are useful when attempting to define other lexical items) of the words selected (Gilner, 2011).Methodology

The method

Qualitative research is the study of the nature of phenomena, which includes their quality, different manifestations, the context in which they appear, or the perspectives from which they can be perceived, but excludes their range, frequency, and place in an objectively determined chain of cause and effect ( Philipsen .Beyond Vocabulary Size :Content analysis can extend to examining the broader context of the test, such as the types of texts or tasks used, to ensure they are appropriate for the intended learners and aligned with their language learning goals.Content analysis in reading comprehension tests involves examining the characteristics of the reading passages and the questions used to assess understanding, focusing on aspects like content, cognitive levels, and the types of thinking they elicit.The main difference between skilled and less skilled readers lies in slower and inefficient lexical access and semantic processing (Bernhardt 2005, Grabe and Stoller 2002, Nassaji 2003, Segalowitz et al. 1991).The researchers who created small-scale corpora (Campion & Elley, 1971; Ghadessy, 1979; Praninskas, 1972) included between 300,000 to 500,000 words due to manual word counts, while Coxhead's (2000) scale included around 875,000 words across four disciplines (arts, science, law, and commerce).Instruments Content analysis:

Content analysis in the context of a vocabulary size test refers to the process of examining and categorizing the content of the test itself, often focusing on the words included and their characteristics.In addition, many researchers and authors claim that vocabulary knowledge and reading comprehension are strongly related and several studies have confirmed such a relationship between the two (Hsueh-Chao & Nation, 2000; Schmitt, 2000; Nation, 2001; Zhang, 2012; Karakoc & Kose, 2017.Thus, most students employ non-university strategies to read academic texts, which result in students taking a surface approach to reading (Torgesen, Housten, Rissman, Decker and Roberts 2007).Theoretical background Vocabulary size :

The process of how vocabulary learning takes place is still unclear as it requires various components of knowing a word, taking into consideration that the process of learning vocabulary is gradual in nature leading to continuity (Schmitt, 2000).They generally take them for granted as they tend to presuppose that all students already acquired these skills either as part of their secondary education or elsewhere in other courses at university or college (Erickson, Peters & Strommer, 2006).According to what was presented above and what great many of researchers including (Laufer 1996, Meara 1997, Nation 2001, Read 2000) and many more attest to, the significance of the role of vocabulary in reading comprehension is clearly acknowledged.Hence, working within this context, the present researchers deemed it indispensable to launch a study where vocabulary is paid     little heed to in most reading comprehension courses.To better understand ideas, opinions, or experiences, qualitative research involves gathering and analyzing non-numerical data (such as text, video, or audio).This analysis helps in validating the test, ensuring it effectively measures vocabulary knowledge, and provides insights for test design and interpretation.In addition ,the content vocabulary items in the reading passages were found in the vocabulary lists in the participants' university textbooks, which represents content validity in the reading passages.She selected academic words representing a wide variety of academic disciplines, taking into consideration the different linguistic features that may differ across those disciplines.Stahl (2003: 246) contends that studies from readability formulae have 'found that the most important factor in determining the difficulty of a text is the difficulty of the words.'Research Objectives

The main purpose of this study is to determine the relationship between vocabulary size and reading comprehension of Saudi EFL learners, so this study sought to: .Limitations

The present study aimed at investigating the extent of vocabulary knowledge and the relationship between the vocabulary size and reading comprehension of Saudi EFL learners.It involves analyzing the vocabulary items to understand their frequency, difficulty, and relevance to the intended test-takers.This allows for a content analysis to ensure that the items are graded in difficulty and representative of the target vocabulary range.In the context of reading comprehension tests, it involves analyzing: Content of the passages& Cognitive levels of questions.Fast and efficient word recognition, word encoding and lexical access are necessary for a higher level of meaning construction (Adams 2004, Just and Carpenter 1987, Lesgold and Perfetti, 1978).A number of studies have revealed consistent correlations between vocabulary and comprehension (Laufer 1992a, 1992b, Qian 1999, 2002, Nation 2001).What is missing is a blithe disregard for vocabulary in approaching reading comprehension, particularly in the EFL setting of KSA.Q2 To what extent does vocabulary knowledge contribute to reading comprehension among Saudi EFL learners?There is no accurate number of words to be known for native speakers or language learners since the number of words is continuously changed (Karakoc & Kose, 2017).Campion & Elley (1971) and Praninskas (1972) created academic word lists based on small corpora, in which they counted words by hand.This large corpus has been divided into roughly equal sections to calculate the range of academic vocabulary across the entire corpus, and then the size of the corpus is considered.Zimmerman (1997) pointed out that extensive reading on various texts leads to expanding the vocabulary knowledge.To this end, the study aims to answer the following research question: Does vocabulary size have any effect on reading comprehension of Saudi EFL learners?During the exploratory phases of a study, educators use qualitative research to find patterns or fresh perspectives.This article discussed the approaches to qualitative research, qualitative data collection methods, advantages and disadvantages of qualitative research and tools for analyzing qualitative data.The present study does not focus on any vocabulary acquisition problems that learners might face, but seeks to investigate the level of their vocabulary knowledge and its relationship with reading comprehension.The two reading passages are associated with 10 multiple-choice questions, and each correct answer was assigned one point; so the maximum possible score of the reading comprehension test was 10 points.The accurate use of words can be achieved through the knowledge of the words' pronunciation and spelling; however, it is clear that the real knowledge of words goes beyond these two aspects (Schmitt,2008).Other researchers have turned to pedagogical word lists to help learners prioritize their vocabulary learning.Ghadessy (1979) devised an academic word lists based on notes made in textbooks by students, indicating words they faced for the first time.Xue & Nation (1984) used the lists from the aforementioned studies and created a large-scale academic word list, which they called the University Word List (UWL).To understand text meaning, one must be able to decode the printed message (Adams 2004, Alderson 2000, Day and Bamford 1998).Vocabulary knowledge is one of the contributing factors for comprehending reading texts (Nation & Coady, 1988).Research Questions: The study attempted to answer the following questions: Q1 What is the extent of the vocabulary size of Saudi EFL learners?A more practical guideline can be added to this formal definition: qualitative research typically includes data in the form of words instead of numbers ( Punch, K. F. , 2013).The aim of qualitative research is to gain a comprehensive understanding of social phenomena in their natural environments.It relies on the direct experiences of people as meaning-making agents in their daily lives and focuses on the why rather than what of social phenomena (Fossey , E.,2002).Finding insights that can result in testable hypotheses is the main goal of the data collection, which is frequently done in narrative form.Determine the vocabulary size of Saudi EFL learners.Examine the relationship between vocabulary size and reading performance among Saudi EFL learners.The researcher does not claim that the results are representative as regional academic differences may exist between students from different places in the Kingdom.This test includes four parts, which provide estimate of vocabulary size at 2000, 3000, 5000, and 10,000-word frequency levels.It also includes all the words in each group that represent the same type of word with no syntactic clues for the accurate matches (Varnaseri, 2016).The test encompassed two reading passages and they were taken from one TOEFL preparation manual.Learning high-frequency words is one of the vocabulary challenges facing EFL learners.Coxhead (2000) used a more representative list of academic words based on the principles of corpus linguistics.The presence of high density of unknown words in a text may seriously hinder comprehension (Curtis 1987, Nation, 2001).A number of scholars and authors have emphasized the relationship between vocabulary size and reading comprehension.Hsueh-Chao & Nation (2000) emphasized the relationship of vocabulary knowledge on reading comprehension as well as the relationship between reading comprehension and vocabulary knowledge.Despite the importance of these skills for academic success, lecturers seldom teach them .A methodology called qualitative research is created to gather non-numerical data to produce insights.It is not statistical and is either semi-structured or unstructured.It is predicated on data gathered using a research methodology that provides an answer to the why.It can be used to uncover intricate details about a situation or to spark fresh research concepts.The modified version of the Vocabulary Size Test has proved that 30 items per level was more reliable than the 18 items found in Nation's (1983) test.The first two parts (2000 and 3000-word frequency levels contain only high frequency words in English; the 5000-word frequency level falls between high-frequency words and low-frequency words; and the 10,000-word frequency level includes low-frequency words.This version of the test contains ten clusters in which six words and three definitions are provided.West's selection of those words was primarily based on frequency, assuming that these words are the most essential words for foreign language learners.Vocabulary size is thus a strong predictor of reading comprehension.Hills & Laufer (2003) indicated that post-reading tasks that focus on target vocabulary lead to better vocabulary knowledge.These include reading, writing, critical thinking, oral presentation, and media literacy.The reality is that most first-year students lack academic reading skills, especially because university-level reading greatly differs from high school reading.The first passage was about British Columbia and had 117 words; and the second passage was about Rain and was 242 words in length.In order to help learners, overcome this, West (1953) created a word list known as the General Service List (GSL).GSL words were obtained from a 2.5million word corpus.Many attempts have been made to create academic word lists.This list was widely used for several years in a variety of teaching and research contexts.Vocabulary size seems to play a vital role in reading comprehension.This fact simply goes unnoticed by a host of KSA teachers.Qualitative research is concerned with feelings, ideas, or experiences.This vocabulary test was chosen because it reduces the guessing to one response among six choices.The participants are expected to match the word with its correct definition.Clock _6 part of a house 3.Horse _3 animal with four legs 4.Pencil _4 something used for writing 5.These two reading passages were chosen due to their suitability to the students' level.Vocabulary Size and Reading Comprehension

The role of vocabulary in reading comprehension is a complex one.frequency.The following is an example taken from the 2000-word frequency level: l. Business 2.Wall Reading Comprehension Test: The reading comprehension test was the second instrument used in the present study.H., 2007)..Shoe 6.

Research Problem
   Success at university level mainly depends on existing pre-entry university attributes, including the mastery of some fundamental academic skills (Tinto, 1993). These include reading, writing, critical thinking, oral presentation, and media literacy. Despite the importance of these skills for academic success, lecturers seldom teach them . They generally take them for granted as they tend to presuppose that all students already acquired these skills either as part of their secondary education or elsewhere in other courses at university or college (Erickson, Peters & Strommer, 2006). The reality is that most first-year students lack academic reading skills, especially because university-level reading greatly differs from high school reading. Thus, most students employ non-university strategies to read academic texts, which result in students taking a surface approach to reading (Torgesen, Housten, Rissman, Decker and Roberts 2007).
   According to what was presented above and what great many of researchers including (Laufer 1996, Meara 1997, Nation 2001, Read 2000) and many more attest to, the significance of the role of vocabulary in reading comprehension is clearly acknowledged. What is missing is a blithe disregard for vocabulary in approaching reading comprehension, particularly in the EFL setting of KSA. This fact simply goes unnoticed by a host of KSA teachers. Hence, working within this context, the present researchers deemed it indispensable to launch a study where vocabulary is paid     little heed to in most reading comprehension courses. To this end, the study aims to answer the following research question: Does vocabulary size have any effect on reading comprehension of Saudi EFL learners?
Research Questions:
  The study attempted to answer the following questions:
Q1 What is the extent of the vocabulary size of Saudi EFL learners?
   Q2 To what extent does vocabulary knowledge contribute to reading comprehension     among Saudi EFL learners?
Methodology
 
The method
 
   Qualitative research is the study of the nature of phenomena, which includes their quality, different manifestations, the context in which they appear, or the perspectives
from which they can be perceived, but excludes their range, frequency, and place
in an objectively determined chain of cause and effect ( Philipsen . H., 2007). A more practical guideline can be added to this formal definition: qualitative research typically includes data in the form of words instead of numbers ( Punch, K. F. , 2013).
   The aim of qualitative research is to gain a comprehensive understanding of social
phenomena in their natural environments. It relies on the direct experiences of people
as meaning-making agents in their daily lives and focuses on the why rather than
what of social phenomena (Fossey , E.,2002). For the study of human phenomena, qualitative researchers employ a variety of systems of inquiry, such as biography, case study, historical analysis, discourse analysis, ethnography, grounded theory, and phenomenology, as opposed to logical and statistical methods.
    Qualitative research is concerned with feelings, ideas, or experiences. Finding insights that can result in testable hypotheses is the main goal of the data collection, which is frequently done in narrative form. During the exploratory phases of a study, educators use qualitative research to find patterns or fresh perspectives. A methodology called qualitative research is created to gather non-numerical data to produce insights. It is not statistical and is either semi-structured or unstructured. It is predicated on data gathered using a research methodology that provides an answer to the why. This article discussed the approaches to qualitative research, qualitative data collection methods, advantages and disadvantages of qualitative research and tools for analyzing qualitative data.
   To better understand ideas, opinions, or experiences, qualitative research involves gathering and analyzing non-numerical data (such as text, video, or audio). It can be used to uncover intricate details about a situation or to spark fresh research concepts. 
Research Objectives
 
   The main purpose of this study is to determine the relationship between vocabulary size and reading comprehension of Saudi EFL learners, so this study sought to:
·      Determine the vocabulary size of Saudi EFL learners.
·      Examine the relationship between vocabulary size and reading performance among Saudi EFL learners.
   

Limitations
 
The present study aimed at investigating the extent of vocabulary knowledge and the relationship between the vocabulary size and reading comprehension of Saudi EFL learners. The researcher does not claim that the results are representative as regional academic differences may exist between students from different places in the Kingdom. The present study does not focus on any vocabulary acquisition problems that learners might face, but seeks to investigate the level of their vocabulary knowledge and its relationship with reading comprehension.
Instruments
Content analysis:
 
   Content analysis in the context of a vocabulary size test refers to the process of examining and categorizing the content of the test itself, often focusing on the words included and their characteristics. It involves analyzing the vocabulary items to understand their frequency, difficulty, and relevance to the intended test-takers. This analysis helps in validating the test, ensuring it effectively measures vocabulary knowledge, and provides insights for test design and interpretation. frequency. This allows for a content analysis to ensure that the items are graded in difficulty and representative of the target vocabulary range.
   Beyond Vocabulary Size :Content analysis can extend to examining the broader context of the test, such as the types of texts or tasks used, to ensure they are appropriate for the intended learners and aligned with their language learning goals.
   Content analysis in reading comprehension tests involves examining the characteristics of the reading passages and the questions used to assess understanding, focusing on aspects like content, cognitive levels, and the types of thinking they elicit. This analysis helps in evaluating the quality and effectiveness of the reading comprehension assessment and the extent to which it promotes different levels of thinking .Content analysis is a research method used to systematically examine and categorize the content of text, including reading passages and comprehension questions. In the context of reading comprehension tests, it involves analyzing: Content of the passages& Cognitive levels of questions.
   Vocabulary Size Test:  The VST provided a quantitative measure of the participants’ vocabulary size so that the scores could be collated and subjected to statistical data analysis The Vocabulary Size Test employed in this study was originally developed by Nation (1983) and later it was amended and revised by Schmitt et al. (2001). The modified version of the Vocabulary Size Test has proved that 30 items per level was more reliable than the 18 items found in Nation’s (1983) test. This test includes four parts, which provide estimate of vocabulary size at 2000, 3000, 5000, and 10,000-word frequency levels. The first two parts (2000 and 3000-word frequency levels contain only high frequency words in English; the 5000-word frequency level falls between high-frequency words and low-frequency words; and the 10,000-word frequency level includes low-frequency words. This vocabulary test was chosen because it reduces the guessing to one response among six choices. It also includes all the words in each group that represent the same type of word with no syntactic clues for the accurate matches (Varnaseri, 2016). This version of the test contains ten clusters in which six words and three definitions are provided. The participants are expected to match the word with its correct definition. The following is an example taken from the 2000-word frequency level:
l. Business
2. Clock _6 part of a house
3. Horse _3 animal with four legs
4. Pencil _4 something used for writing
5. Shoe
6. Wall
  Reading Comprehension Test: The reading comprehension test was the second instrument used in the present study. The test encompassed two reading passages and they were taken from one TOEFL preparation manual. The first passage was about British Columbia and had 117 words; and the second passage was about Rain and was 242 words in length. The two reading passages are associated with 10 multiple-choice questions, and each correct answer was assigned one point; so the maximum possible score of the reading comprehension test was 10 points. These two reading passages were chosen due to their suitability to the students’ level. In addition ,the content vocabulary items in the reading passages were found in the vocabulary lists in the participants’ university textbooks, which represents content validity in the reading passages.
 
Theoretical background
Vocabulary size :
 
    The process of how vocabulary learning takes place is still unclear as it requires various components of knowing a word, taking into consideration that the process of learning vocabulary is gradual in nature leading to continuity (Schmitt, 2000). The accurate use of words can be achieved through the knowledge of the words’ pronunciation and spelling; however, it is clear that the real knowledge of words goes beyond these two aspects (Schmitt,2008). Firth (1957) stated, “You shall know the word by the company it keeps” (p.11). The intended message of Firth’s citation here is to classify words not only on the basis of their meanings, but also on the basis of their co-occurrence with other words. Word collocation includes the distribution of word uses and senses, comparing the use of synonymous words, and dictionary definitions. Investigating the use of synonymous distribution enables learners to determine the contextual preferences associated with other collocates (Firth, 1957).
   Nation (2001) provides a comprehensive framework of the information that is necessary to improve word use at different levels. The information consists of three components: form, meaning, and use. Each class encompasses three different aspects of knowing a word, in which he also split the knowledge of words into two types: receptive and productive knowledge. These components and sub-components are made to enable learners to differentiate their capabilities to receive language input through reading or listening and understand it. In addition, the aforementioned components help to distinguish the learners’ ability to produce oral or written words in an appropriate context, utilizing the proper spelling and pronunciation. The ‘form’ aspect involves the written and spoken knowledge that learners should take into consideration when learning new words. The aspect of ‘meaning’ includes words’ meanings, concepts, referents, and the association of words. The aspect of ‘use’ covers the grammatical functions of words, their collocations, and their use restrictions. The following table illustrates Nation’s framework (2001) regarding vocabulary knowledge.
   Nation (2001) classified vocabulary knowledge into 18 questions grouped into three categories, in which each category contains receptive and productive aspects. The framework defines vocabulary knowledge from different perspectives: pragmatic, semantic, and morphological perspectives and it shows that all of the aspects are closely interrelated. For instance, the meaning of a word could be derived from the context or the form of that word (Gu, 2017). However, Nation realizes that this framework is incomplete and needs modification. He indicates the difficulty of measuring vocabulary knowledge by only using this classification. He also added that the aspects of this classification are interrelated with each other, which makes differentiating between certain words difficult.
    Vocabulary size refers to the amount of vocabulary needed to understand and use the language (Karakoc & Kose, 2017). Language learners need to expand their vocabulary size since “vocabulary is a continually changing entity with new words and new uses of old words being added and old words failing into disuse” (Nation & Waring, 1997, p. 6). There is no accurate number of words to be known for native speakers or language learners since the number of words is continuously changed (Karakoc & Kose, 2017). Learning high-frequency words is one of the vocabulary challenges facing EFL learners. In order to help learners, overcome this, West (1953) created a word list known as the General Service List (GSL). GSL words were obtained from a 2.5million word corpus. West’s selection of those words was primarily based on frequency, assuming that these words are the most essential words for foreign language learners. The selection of those words has also taken into consideration the words’ universality (words are that are used across countries where English is the primary medium of communication), utility (words that cover a broad range of genres), and usefulness (words that are useful when attempting to define other lexical items) of the words selected (Gilner, 2011). Other researchers have turned to pedagogical word lists to help learners prioritize their vocabulary learning. Many attempts have been made to create academic word lists. Campion & Elley (1971) and Praninskas (1972) created academic word lists based on small corpora, in which they counted words by hand. Ghadessy (1979) devised an academic word lists based on notes made in textbooks by students, indicating words they faced for the first time. Xue & Nation (1984) used the lists from the aforementioned studies and created a large-scale academic word list, which they called the University Word List (UWL). This list was widely used for several years in a variety of teaching and research contexts. Coxhead (2000) used a more representative list of academic words based on the principles of corpus linguistics. She selected academic words representing a wide variety of academic disciplines, taking into consideration the different linguistic features that may differ across those disciplines. This large corpus has been divided into roughly equal sections to calculate the range of academic vocabulary across the entire corpus, and then the size of the corpus is considered. The researchers who created small-scale corpora (Campion & Elley, 1971; Ghadessy, 1979; Praninskas, 1972) included between 300,000 to 500,000 words due to manual word counts, while Coxhead’s (2000) scale included around 875,000 words across four disciplines (arts, science, law, and commerce).
 
Vocabulary Size and Reading Comprehension
 
   The role of vocabulary in reading comprehension is a complex one. To understand text meaning, one must be able to decode the printed message (Adams 2004, Alderson 2000, Day and Bamford 1998). The presence of high density of unknown words in a text may seriously hinder comprehension (Curtis 1987, Nation, 2001). Fast and efficient word recognition, word encoding and lexical access are necessary for a higher level of meaning construction (Adams 2004, Just and Carpenter 1987, Lesgold and Perfetti, 1978). The main difference between skilled and less skilled readers lies in slower and inefficient lexical access and semantic processing (Bernhardt 2005, Grabe and Stoller 2002, Nassaji 2003, Segalowitz et al. 1991).
   A number of studies have revealed consistent correlations between vocabulary and comprehension (Laufer 1992a, 1992b, Qian 1999, 2002, Nation 2001). Stahl (2003: 246) contends that studies from readability formulae have ‘found that the most important factor in determining the difficulty of a text is the difficulty of the words.’ Vocabulary size is thus a strong predictor of reading comprehension. Within the context of L2 research in reading, findings on the reading processes and vocabulary threshold have consistently indicated the importance of vocabulary knowledge in reading comprehension (Fukkink et al. 2005, Garcia 1991, Koda 1994, Laufer, 1997, Zhang 2000, 2002a, 2002b; see Alderson 2000, Bernhardt 2005, and Nation 2001, for reviews).
    Vocabulary size seems to play a vital role in reading comprehension. Vocabulary knowledge is one of the contributing factors for comprehending reading texts (Nation & Coady, 1988). A number of scholars and authors have emphasized the relationship between vocabulary size and reading comprehension. Zimmerman (1997) pointed out that extensive reading on various texts leads to expanding the vocabulary knowledge. Hills & Laufer  (2003) indicated that post-reading tasks that focus on target vocabulary lead to better vocabulary knowledge. Hsueh-Chao & Nation (2000) emphasized the relationship of vocabulary knowledge on reading comprehension as well as the relationship between reading comprehension and vocabulary knowledge. In addition, many researchers and authors claim that vocabulary knowledge and reading comprehension are strongly related and several studies have confirmed such a relationship between the two (Hsueh-Chao & Nation, 2000; Schmitt, 2000; Nation, 2001; Zhang, 2012; Karakoc  & Kose, 2017. Pringprom (2012, p.1104) stated, “Learners will have difficulty comprehending the text if their vocabulary size is far from the required threshold”. It is also pivotal to remember that there are also additional factors that affect reading comprehension other than vocabulary knowledge, such as the impact of L1 transfer, individual variance, and the difficulty of texts (Thomas & Healy, 2012).
     According to Krashen and Terrell (1983), vocabulary provides opportunities for students to be successful in the classroom because it relates to knowledge acquisition by the students. Meara (1996) claims that language learners who know a significant amount of vocabulary will be likely to use the four English skills well. When language learners have a broader vocabulary, they comprehend a language better. In fact, Laufer (1989) was more specific when she revealed the importance of having sufficient vocabulary for reading comprehension, claiming that a reader whose vocabulary is insufficient to cover at least 95% of the words in a passage will not be guaranteed comprehension. Readers themselves consider vocabulary knowledge to be the main obstacle to second language reading comprehension. However, Nation (1990) argued that a person’s knowledge of a word should entail both receptive and productive knowledge, all aspects of what is involved in knowing a word, which includes forms, meaning and usage.
    Nation (1990/2001) divided vocabulary knowledge into two types: receptive and productive vocabulary knowledge. Nation (2001) defined receptive vocabulary as knowledge of words or lexical units that the language learners recognize and understand the meaning from either by listening and reading, but may not be able to use the words productively in communication. Receptive knowledge is the language input that learners acquire from others through listening or reading and trying to comprehend it. On the other hand, productive knowledge is the language output that learners use to communicate to others through either speaking or writing. Therefore, listening and reading tasks would require receptive vocabulary knowledge whereas speaking and writing tasks would require productive vocabulary knowledge.
    Learners’ lexicon has two important aspects known as breadth and depth of vocabulary knowledge. Breadth of vocabulary knowledge refers to linear and one-dimensional aspects while depth is related not only to word meanings but also to semantic relationships, collocations and syntactic patterning. Nation (2001) defines the breadth of vocabulary as vocabulary size, or the number of words for which a learner has at least some minimum knowledge of meaning. Depth of vocabulary knowledge, on the other hand, is defined by Read (1993) as a learner’s level of knowledge of various aspects of a given word, or how well a learner knows this word. This kind of knowledge mostly comes from implicit learning of words through extensive reading (Cobb, 1999). Knowing a word involves much more than being able to recall the meaning of a foreign word in your language (Ünaldı, 2011); other factors such as pronunciation, spelling, word associations, limitations, discourse features, frequency of the word in the target language and many other aspects are also to be considered (Akpinar, 2013; Milton, 2009; Nation, 1994; Qian, 1998) .
 
   Literacy instruction
 
   Literacy instruction refers to the integrated teaching of reading, vocabulary, and writing, with a focus on improving reading comprehension and written expression. It involves teaching word meanings throughout the reading and writing processes and provides students with special needs multiple opportunities to practice and enhance their literacy skills.
   Adult literacy education takes place in a wide range of settings where learners engage in a variety of ways with texts of all kinds. It is critical for effective instruction that both the method and the content of instruction recognize this diversity and that deficit approaches, where the learner is assumed to have something wrong with them, are avoided. Instead, a variety of outcomes of literacy instruction should be valued.
   Phonemic Awareness: is the ability to hear, think about, and manipulate the sounds in spoken language. In order for students to effectively learn to read, they must understand that words are composed of phonemes (the smallest unit of sound) in spoken language and they must be able to blend, segment, and manipulate those sounds to form words. Phonemic awareness is one of the best predictors of how well a child will learn to read.  Direct instruction in phonemic awareness includes having children listen to spoken language and determine how to blend sounds together to make words, separate sounds to write words, and move sounds around to make new words.
   Phonics is understanding the relationship between the sounds you hear in spoken language and the letters that represent those sounds. Phonics instruction teaches students how this relationship is used to read and spell. Phonics instruction begins with teaching individual letter sounds and then progresses to teaching complex letter, sound, and spelling patterns. While some children may naturally understand these relationships, research has shown that children who receive systematic instruction of letter-sound relationships and spelling patterns are better equipped to read and spell more accurately and fluently (National Reading Panel, 2000)
     Fluency is the ability to read with accuracy, automaticity, and appropriate expression (prosody). A student who reads fluently reads as though they are speaking. Fluency instruction is important because the larger sight vocabulary a student has (the ability to read words without hesitation) the more mental energy they can expend on comprehension of text (National Reading Panel, 2000). Fluency can be addressed through engagement with appropriate text, re-reading practices, and modeling of fluent reading.
     Vocabulary refers to understanding the meaning of words both in oral language and writing. Vocabulary instruction is closely tied to comprehension of text. Vocabulary must be taught both directly and indirectly. In some cases vocabulary should be targeted through exposure with short explanation, while in other cases, teacher should identify specific vocabulary and teach it in depth to deepen student understanding and connection of selected words.
     Reading comprehension is the ability to understand and interpret information that is read in text. Comprehension is the reason for reading. Students must learn strategies to foster the process of making meaning of text and communicating that meaning in a variety of ways. Comprehension strategies require student to engage in their understanding of text before they read, while they are reading, and after they are reading.
 
Previous studies
 
    Koda's (1989) study of 24 college students who were learning Japanese as a foreign
language found equally strong correlations between a self-made vocabulary test and two reading tests, one being a cloze test and the other paragraph comprehension. Koda
reported a correlation of .69 between the learners' scores on the vocabulary test and the
cloze test, and a correlation of .74 between their scores on the vocabulary test and the
paragraph comprehension test.
     Research by Coady et al. (1993) with 79 students studying English in a university academic preparation program found that two experimental groups, which had received special training in high frequency vocabulary, achieved better ESL reading comprehension at the end of the experiments than did a control group which had not received such a treatment. The study was carried out to verify the proposition that ‘there is a positive and significant relationship between knowledge of high-frequency words and reading proficiency .They argued that special training in the 2000 most frequent English vocabulary items could improve learners' reading proficiency. Besides, investigating the impact of vocabulary on ESL reading, Qian (1999) found a high correlation (r = .82) between the scores on the Vocabulary Levels Test and scores on the reading subset of the TOEFL.
    Laufer & Nation,( 1999) for collecting the data used in their study. The results of this study showed that the students’ receptive vocabulary knowledge was higher than their productive vocabulary knowledge. The results also revealed a significant relationship between vocabulary knowledge and reading comprehension.
    Sasan Baleghizadeh (2010) The present study endeavored to examine this variable to discover its effect on reading comprehension ability of KSAian EFL learners. In so doing, 83 KSAian first-year university students (22 males and 61 females) were given a vocabulary size test (Nation 1990) and a reading comprehension test (TOEFL version 2004). The results showed a very significant correlation between vocabulary size and reading comprehension (r = .84, p < .05), which points out the necessity of improving the learners' vocabulary size in coping with reading passages. However, the high correlation found in this study calls for more replications to add to the precision of such a relationship.
    Treffers-Daller, J. (2013) The study in this paper uses the frequency-based vocabulary size test from Goulden et al (1990) and investigates the vocabulary knowledge of undergraduates in three British universities. The results suggest that monolingual speaker vocabulary sizes may be much smaller than is generally thought with far less variation than is usually reported. An average figure of about 10,000 English words families emerges for entrants to university. This figure suggests that many students must struggle with the comprehension of university level texts.
   Yusuf Şen (2015) The aim of this study is to determine the effects of vocabulary size and vocabulary depth on reading performance in EFL context. To this end, Vocabulary Size Test by Nation and Beglar (2007), Words Associate Test by Read (1998), and a reading performance test, the reliability of which was found to be .81 were administered to 361 university students. In the analysis of the data, linear regression and Pearson correlation statistics were used. The results showed that vocabulary size and vocabulary depth were both significantly correlated to reading performance, but vocabulary depth predicted reading performance better.
    Engku Haliza (2016) The purpose of the study is to examine the relationship between students’ reading comprehension skills and their vocabulary size. A total of 129 pre university students undergoing an intensive English language programme at a public university in Malaysia participated in this study. A correlational analysis was employed to ascertain the relationship between scores in the reading comprehension component of the institutionalised English Proficiency Test (EPT) and the Vocabulary Levels Tests (Nation, 1990). Based on Pearson product moment correlation coefficient, there was a moderate correlation (r=0.641) between scores in the EPT reading comprehension and Vocabulary Levels Tests. The relationship was statistically significant at p