US Extended Input Source missing I'm wanting to type some Pinyin characters (e.g. adding a bar above an a with Alt A + A) and am following this guide http://pinpinchinese.com/blog/how-to-type-pinyin-tone-marks-mac-os-x-yosemite/

However, I don't see the option of a US Extended Input source. Here's what I do see:



Any suggestions?

Fwiw, I'm running El Capitan 10.11.2 (15C50).
In El Capitan the US Extended keyboard was renamed to ABC Extended.