What Chinese is, in short
Chinese is a family of Sinitic languages, part of the Sino-Tibetan family, spoken by about 1.3 billion people. Its standard form, Mandarin (Putonghua), has more native speakers than any other language. It is written with characters, each standing for a syllable with a meaning, rather than with an alphabet.
The pitch is part of the word
Characters are built, not drawn
Very few characters are pictures. Most combine parts: a radical that hints at meaning, often joined to a part that hints at sound. Learn the parts and thousands of characters stop being random.
Time changes; the verb doesn't
Mandarin verbs never change form. Time is shown with time words like “yesterday” and small particles like 了 (le) for completion or 过 (guo) for experience. Pick a time and watch only the extra words move.
Many spoken, one written
The main varieties are often called dialects, but a Cantonese and a Mandarin speaker may not understand each other's speech. They can read the same written standard.
Harder than it looks, easier than you'd think
3,000 years of continuous writing
Chinese is one of the oldest writing systems still in use. A modern reader can recognise many characters carved more than 2,000 years ago.