This paper investigates the functions of the epistemic stance adverb talan 'perhaps' both on the basis of a corpus of written texts and on that of spoken utterances. The comparison revealed differences between the two text types (1) in the frequency of occurrence of talan, (2) in the presence or lack of certain functions, and (3) in the proportions of functions that are present in both corpora. (1) The lexeme talan occurred approximately 3.5 times as often in the 'spoken' text type as in the 'written' corpus. (2) Accumulation of stance adverbs, postposed talan, and overt quotative evidence only occurred in the spoken corpus, whereas it was only in the written corpus that an accumulation of several possible assumptions was indicated by talan. (3) Spoken texts were characterized by clause-initial position, the politeness function, and indication of indirect speech acts by talan to a higher extent; written texts more often exhibited the epistemic function of talan and its role in making statements vaguer. The testing of the various functions of stance adverbs may be facilitated by the observation that talan, in its epistemic function, can be replaced by another stance adverb of a similar modal strength (e.g., esetleg 'maybe', feltehetoleg 'presumably', valoszínuleg 'probably'); in its non-modal, pragmatic functions, however, it can only be substituted for by esetleg.