I think you translate "speak" into "shuo hua" (说话). 说话 actually means "speak words". It is only used when there are no nouns after the word "speak". (“谁在说话” means "who is speaking".) If you want to say "speak Chinese", you have to say “说中文” instead of "说话中文“. Although "文" means the written forms, "中文" sometimes can be also used to indicate the oral forms. In fact, the written part of Chinese is usually called "汉字” (Chinese characters).

Do you mean "話中文"? If so, it isn't a natural vocabulary heard in Chinese speaking. If you are trying to say Mandarin, then it's 國語. Otherwise, you can simply say 中文

Actualy you can't even say like this or like it is suggested in test, because 文 is only used for written forms of language. You can't say a symbol, though only 汉语，国语，普通话 etc would be clear

会 has a second meaning of "can" in the sense of "know how to".

The "can" in "Can you speak Chinese?" is referring to ability, not permission. "你可以説中文嗎？" -> Is it OK for you to speak chinese?