Since my last examination of the selection at Google Web Fonts the number of font families for Latin Extended has reached 98 [edit: May 31, 2012: 188], with one new face capable of rendering Hanyu Pinyin with tone marks: Noticia Text.
Here are the Pinyin-friendly font faces at Google Web Fonts.
- EB Garamond
- Gentium Basic
- Gentium Book Basic
- Noticia Text
- Ubuntu Condensed
- Ubuntu Mono
For future reference, the font most recently added to the Latin Extended group is Ruda [edit in May 2012: Chau Philomene One], which doesn’t support Pinyin with diacritics (except, perhaps, through combining diacritics).
- Google Web fonts and Pinyin — December 2011 update, Pinyin News, December 16, 2011
- Google Web fonts and Hanyu Pinyin, Pinyin News, September 21, 2011