This book introduces the theory and practice of semantics in modern linguistics, focusing on the investigation of speakers' linguistic knowledge.  A core assumption is that linguistic abilities stem from inherent knowledge. Modern linguistics recognizes different types of linguistic knowledge: phonology (sound system), syntax (sentence structure), and semantics (meaning of words and sentences).  These levels are distinct; one can know a word's meaning without its pronunciation, or vice-versa.  Similarly, knowing a word's meaning might not encompass knowledge of its plural or genitive forms.  Therefore, knowing a word integrates various types of knowledge, mirroring the interconnectedness of knowledge in phrase and sentence construction.  Since linguistic description aims to reflect a speaker's knowledge, semantic description focuses on this semantic knowledge.  This is exemplified by the understanding that certain sentences, despite differing forms, describe identical situations.