This paper examines the use of the modal auxiliaries can and could in speech acts produced by university students of English. Its aim is to explore syntactic patterns, semantic features and pragmatic functions of utterances containing can/could in Corpus of Czech Students’ Spoken English. Taking account of pragmatic factors, including broader linguistic and extralinguistic context, the analysis attempts to identify the illocutionary forces conveyed by the modalized speech acts excerpted from the corpus dialogues. The findings indicate that the modal verbs are commonly employed as a modifying device in indirect speech acts, particularly in conventionalized directives. As for their frequency of occurrence, can proves to be a widely used modal auxiliary in spoken learner discourse, whereas the more remote could appears in the corpus much less frequently in that it is associated with a higher degree of diffidence.
