gonna = going to gotta = got to wanna = want to dunno = don't know Wahab, I am surprised you found these in texts! These are colloquialisms which I always advise students of English to avoid using until they are very familiar with the language. Even then I think they should be avoided. These colloquialisms are popular with many younger people.

Sometimes these "want to, don't know, got to" are pronounced so indistinctly that could be easily taken for "wanna, dunno, gotta" and otherwise. Curiously enough, it is clearer with "gonna". For me there is very slight verge in the pronunciation of these words. I wonder even if native speakers can always say for sure either it's said "dunno" or "don't know" for example. (maybe there is a similar situation in Russian: for example the words "это" and "эта" can be pronounced the same as well as differently)