I dunno for I do not know. That's a cursory way to tell it. I'd like to know if dunno can be used at other persons singular or plural than the first one. Tks.
Look at the nearby post "you should be able find your thing" instead of "be able to find", a word has been dropped. In the same way of casual speech, the subject of dunno is sometimes left out. "Dunno" for "I dunno". About your question, I can't tell anything but what I can imagine. Ex. - Will it be raining this afternoon? - Dunno. - You dunno? Though you got the weather forewast.
"Don't" can be used after every grammatical person except 3rd person singular. The same applies to "dunno". (For 3rd person singular, we say "doesn't know").
