20 most common words in informal speech

i, you, it, the, 's, and, n't, a, that, yeah, he, to, they, do, oh, what, is, of, was, in

20 most common nouns in informal speech

time, thing, people, way, mum, day, things, week, night, money, bit, car, morning, lot, dad, year, house, pound, school, years

20 most common verbs in informal speech

's, do, is, was, 've, got, know, did, 're, 'll, be, said, had, are, can, 'm, get, do, were, have

30 most common adjectives in informal speech

good, nice, right, other, little, big, old, alright, new, sorry, lovely, bad, bloody, different, sure, funny, better, only, long, great, able, wrong, supposed, black, best, red, full, fucking, stupid, whole

30 most common adverbs in informal speech

well, just, there, then, so, up, now, out, really, right, here, how, on, down, why, very, back, only, where, never, off, all, quite, in, again, still, actually, anyway, much, alright

[source: British National Corpus]

A complete list of words with their frequencies in informal spoken English can be found here [xls spreadsheet].

   
  (c) Vaclav Brezina 2013