Hedging verbs (suggest, indicate, estimate, assume)
Verbs (appear, seem)
Expressions (according to, on the basis of, based on)
Modal verbs (may, might, could, can)
Adverbs (probably, seemingly, presumably, perhaps, apparently)
Adjectives (probable, possible, uncertain, unlikely)
Nouns (probability, possibility, assumption, evidence, likelihood, claim)
Approximators (approximately, roughly, about, often, occasionally, generally, usually, somewhat, somehow, a lot of)