啦 is an emotional word used at the end of sentences to express speaker's emotion or feeling at that time. in this sentence,不需要问你的啦。 the meaning or the emotion it express depends on the context. It can be showing the speaker lost his patience. and/or also speaker don't want to talk to the guy any more. Hope this help.

啦 is one of the many interjections you hear in Chinese, its meaning kinda varies depends on what context you are using it in, in most cases it is used for expressing your emotions and helps you express your ideas in a "soft" way. Interjections are seen in English as well, such as uh, huh, oh, doh, ouch and so on.

I agree with the anwer above.but there are some ppl like to speak in this way especially girls.They put "啦"in the end of sentence frequently. In that case,the "啦" makes no sense.

其实这句话可以直接说"不需要问你的" 多加一个"啦" 1.使语气更委婉(在这句子中起到的作用) 以上仅仅是"啦"作用之一