Chinese
Chinese is the spoken and written language of China. What exactly does this mean? For most people most of the time, this means Standard Chinese or "Mandarin". Learning how to speak and read this language, however, does not mean you will be able to understand or use other things called "Chinese" such as Literary/Classical Chinese, Cantonese, or even the regional dialects of Beijing. In Chinese, the standard variety is more precisely called 普通话 pǔtōnghuà "standard speech". If you speak "good Chinese", you may be told your speech is 很标准 hěn biāozhǔn "very standard/correct".
See my page on learning Chinese for practical tips on learning/studying Chinese.
The Chinese Language
What sort of language is Chinese? What follows is a brief linguistic description of Chinese. See my article on Chinese characters for a more in-depth discussion of Chinese characters.