Chinese Language. Mandarin

A comprehensive course covering Chinese characters, radicals, Mandarin phonetics, pinyin, zhuyin, and grammar fundamentals including pronouns, quantifiers, verbs, and adjectives. From National Chiao-Tung University.

Daniel J. Greenhoe

A complete beginner textbook from Michigan State University covering tones, pinyin, characters, and 7 dialogue-based lessons on everyday topics like introductions, family, food, and phone calls. CC BY-NC 4.0 licensed.

Wenying Zhou

Ten chapters by language specialists covering pronunciation, tones, vocabulary memorization, listening skills, sentence structure, motivation, immersion, technology tools, and character learning methods.

Various authors

An open-content textbook covering Chinese language basics, pinyin pronunciation, tones, and seven structured lessons on greetings, particles, word order, measure words, and interrogatives. Includes both simplified and traditional characters.

Wikibooks