Passage 1

There are more than five thousand languages spoken today. They are so different that most of them are mutually unintelligible. That’s why we need a lot of translators and interpreters.
    We are all intimately familiar with at least one language, yet few of us ever stop to consider what we know about our language and linguistic competence. Many of them even barely know the definition of language.
    We may say that language is a tool of communication. But if language is defined merely as that, then language is not unique to humans. We know birds, bees, whales, and most other creatures communicate in some way.
    A basic property of human language is its creative aspect, that is, a speaker’s ability to combine the basic linguistic units to form an infinite set of grammatical sentences.