how to speak nice to human? because my character is more to savage and mean. give me an idea?

You're supposed to pull from real life, your life and what you see around you.

What does "more to savage mean"? I think you meant "humans". If you need help to write a book, perhaps you're not ready to write yet.

A savage and mean character does not want to "speak nicely" to humans because it is savage and mean. It may be frustrated as well, if it does not know how to speak and understand a human language.

If I am wrong and it does wish to "speak nicely" to humans, and it knows how to read in English, I suggest it go to the library with you and study a book about etiquette. You should go with him to 1) explain all this to the library staff, 2) protect the library users and the collection and 3) borrow the etiquette book.

Perhaps your character doesn't feel like he can connect to others because they don't understand him. Maybe he doesn't fully understand them either. When people lock up feelings and emotions they can often seem distant and mean. It just means they're also distant and mean to themselves.

If you don't feel nice inside, you won't speak nicely to humans. In order to get to speak nicely, you have to come to terms with what's bothering you inside.