Choose the word or phrase ( A, B, C or D ) that best fits the blank space in the following passage. Speech is one of the most important ways of communicating. It consists of far more than just (46)_________noises. To talk or to (47)_________by other people, we have to master a language, that is, we have to use combinations of sound that everyone agrees (48)_________for a particular object or idea. Communication (49)_________impossible if everyone (50)_________up their own language. (46) .................