Babbel

Teaches languages through translation and listening exercises. Also features live lessons with instructors.

Mondly

Gamifies language practice, mainly through translation and listening exercises.

Duolingo

Gamifies language practice, mainly through translation and listening exercises.

Pimsleur

Teaches languages through various methods including audio courses, flash cards, and pronunciation practice.

Chinese: A Comprehensive Grammar textbook grammar

Yip Po-Ching,Don Rimmington
More than half is dedicated to word forms and most of the rest is for sentence structure. There is also a section that describes differences in usage between Mandarin and English.

Chinese: An Essential Grammar textbook grammar

Yip Po-Ching,Don Rimmington
A guide to word forms, syntax, and usage in Mandarin. Also features explanations of paragraph-length writing samples and colloquialisms.

Modern Mandarin Chinese Grammar textbook grammar

Claudia Ross,Jing-Heng Sheng Ma,Baozhang He,Pei-Chia Chen
A guide with one part dedicated to word forms and the other part dedicated to teaching about usage through example situations.

The Handbook of Chinese Linguistics textbook grammar linguistics

Claudia Ross,Jing-heng Sheng Ma
A guide to the various fields (syntax, semantics, phonology, etc.) of Mandarin.

A Reference Grammar of Chinese textbook grammar

Claudia Ross,Jing-heng Sheng Ma

Basic Chinese: A Grammar and Workbook textbook grammar workbook

Po-Ching Yip,Don Rimmington
An introduction to Mandarin grammar accompanied by writing exercises and an answer key.

The Sounds of Chinese with Audio CD textbook pronunciation linguistics

Liu Yuehua,Pan Wenyu,Gu Wei