I don't know what is mean : Boof
Can you tell me what is vietnamese mean ? Or u can explain it with English to express to me ?
I have a picture :

In the top of page, the character express her angry ( so like that ^^! )
The sfx : boof => what is mean ?
And this word : だ so like the word in the picture. But is mean " I ", it not logical. Can some one help me ? Plzz !