Can I just add something here? What IS rude and impolite is when people write 'wanna' , especially when they are asking other people to help them. Italki members often write posts on these pages like this: "I wanna know the meaning of this word." This comes over as very rude indeed. I'm sure I'm not the only native English speaker here whose first reaction is 'Ugh! That looks horrible. I'm not sure I want to help that person.' We really don't like being addressed in this way.

In spoken language, nobody chooses whether to say 'wanna' or 'want to'. There is no choice involved. It is not the same as deciding when to use a formal word or an informal one. Nor is it a question of being rude or polite. If we are speaking slowly and carefully, as we might do in a formal situation, we say 'want to'. When we are speaking in a more casual way, among family and friends, or if we are speaking quickly, especially when we are excited, the two words 'want to;' slur together naturally so that it sounds like we are saying 'wanna'. We don't decide to say 'wanna'. It simply happens. Writing is another matter entirely. Native speakers do not write 'gonna' and 'wanna' , except in certain special situations when we want to imitate speech.

No, they are not rude. They are basically just the way the phrases "going to" and "want to" come out naturally when you speak them quickly and don't work hard to use correct diction. They are not slang. They are not "bad language." They are just informal, casual, lazy, or sloppy pronunciation. They are not real words, and they SHOULD NOT BE USED IN WRITING except within quotation marks where you are trying to convey the spoken language as it is spoken. As with much informal English, I think it is a mistake for non-native speakers to try to use informal or nonstandard English. The first goal is should be to speak English that native speakers can understand easily. If I hear ANY ACCENT AT ALL, I am not EXPECTING to hear informal English, so instead of making it easier to understand, it makes it harder. I will have to listen more closely to what people say, but when I am speaking casually I think that what I actually say is closer to "goyna" than "gonna."

They are not rude,Ashley they are the regular informal way people speak.But you cannot use them with teachers or in exam situations.

'Wanna' and 'gonna' are just informal terms, mostly used in America. You could use them when you're with friends, but using them to a stranger could indeed be a bit impolite I guess.