This article describes the basics of way to teach tones that is different from the traditional way mainly in that the third tone is no longer described as a falling-rising tone (since that is rarel... Read more.

sinosplice.com

A website on the etymology of Chinese characters, with a lot of images of their past forms from different periods. Read more.

chineseetymology.org

This is the best overview of spaced repetition research I have seen online or offline. It's thorough, well-argued and probably covers more than you were looking for. It's not specifically about Chi... Read more.

gwern.net

You can input Charakters and this tool will output statistics about the words and characters, and can suggest high frequency words and characters that should be learned. It also analyses the HSK le... Read more.

hskhsk.pythonanywhere.com

A program to split any Chinese text into individual words, summarizing information about each unique word. The information is presented in the form of a tab-delimited matrix, so that the results ca... Read more.

zhtoolkit.com

This is a basic but fairly comprehensive overview of the phonology of Standard Chinese (or Mandarin, as it might be better known as). This site covers consonants, vowels, syllables, tones, word str... Read more.

en.wikipedia.org

This is a unique resource that shows how most common speech sounds are actually produced. Most other resources use animations and diagrams, but this is the frist I see which show actual MRI scans. ... Read more.

seeingspeech.ac.uk