Modal items are those which carry meanings referring to the degree of certainty
(sometimes called epistemic modality) or necessity (deontic modality).The corpus statistics underscore this earlier
work and provide compelling evidence of the ubiquity of modal items in everyday speech
and writing.To argue that the domain of modality be expanded beyond
the closed-class modal verbs is not a new idea; several linguists have advocated this, based
on the frequent occurrence in written texts of a wider range of modal items (Holmes ????)
or on sociolinguistic 'fieldwork' (Stubbs ????).Clearly the best candidates
for such meanings in the ?,???-word list are the closed class of modal verbs (can, could,
may, must, will, should, etc.