I would like to ask for your help in the followings:
As my mothertounge is not english, i don't know what i can use in letterwriting when it comes to informal letters. What i'd like to ask is wether i can use "gonna", "wanna" and other abbreviated forms of words or phrases in an informal letter, and i would also like to know if i can use phrases like "spill the beans", "hit me back" or "holla back" in informal letters on a language exam.
Thank you for your response in advance.
Even in very informal letters, "gonna" and "wanna" seem strange to me, as if the writer is trying very hard to seem "cool". It may give the wrong impression. To be on the safe side, stick to "going to" and "want to".
Using idioms like "spill the beans" in an exam should impress the examiners, if they know what the idioms mean. Don't use very new idioms from the world of rap and hip-hop; examiners may not understand them, as they belong to a very small community. That includes "hit me back", "holla back" and "fo'shizzle". Even in real life, if you are ever in New York, don't use phrases like this unless you are an expert in their use -- you'll sound foolish if you try and get it wrong.