do your brothers speak japanese is this correct. why we dont use does your brothers speak japanese

correct because brothers are plural with plural we use do

this is correct if u use does it become wrong

"Do your brothers speak Japanese ?" is correct sentence. At first you have to understand where should we use "do" or "does". Do :- In Interrogative Sentence, Do is used in those sentence where the subject is plural. Ex :- Do the boys play cricket ? Does :- In Interrogative Sentence, Dies is used in those sentence where the subject is singular. Ex :- Does she play badminton ? So, the first sentence is correct and the second sentence is incorrect. You should write the second sentence like that :- Does your brother speak Japanese ?

Do your brothers speak Japanese? - correct In this type of sentence, we use do or does. It only depends on the noun that comes after this possessive adjective (my,your,etc). If after it,it comes a singular noun then we use "does" . For ex:- Does my/your sister speak? But if after it, it comes a plural noun then we use "do". Ex:- Do my/your sisters speak?