Directions: Complete the passage by choosing the proper words in the box.

Language is human speech either spoken or written.   It makes it【小题1】        for man to talk to each other and write their 【小题2】   and ideas.   Language is the most 【小题3】       system of communication. The word "language" may be loosely used to mean any system of 【小题4】 , such as traffic lights or Indian smoke signal. But the 【小题5】 of the word shows its basic use. It comes from the Latin word "lingua", meaning "tongue". And language is still very often 【小题6】 a "tongue". For example, a great many people 【小题7】 to choose the expression "mother tongue'' when they speak their 【小题8】 language. About 90 percent of all human communications take place through their【小题9】 language.