switch input (language) quick with keyboard
To get different shortcuts for each input source, save something like this as private.xml in KeyRemap4MacBook:

&lt;?xml version="1.0"?&gt;
&lt;root&gt;
&lt;item&gt;
&lt;name&gt;test&lt;/name&gt;
&lt;identifier&gt;private.test&lt;/identifier&gt;
&lt;autogen&gt;__KeyToKey__ KeyCode::F1, KeyCode::VK_CHANGE_INPUTMODE_ENGLISH&lt;/autogen&gt;
&lt;autogen&gt;__KeyToKey__ KeyCode::F2, KeyCode::VK_CHANGE_INPUTMODE_CHINESE_TRADITIONAL&lt;/autogen&gt;
&lt;autogen&gt;__KeyToKey__ KeyCode::F3, KeyCode::VK_CHANGE_INPUTMODE_FRENCH&lt;/autogen&gt;
&lt;/item&gt;
&lt;/root&gt;


⌥E would be KeyCode::E, VK_OPTION | ModifierFlag::NONE. The input source names are defined in inputsourcedef.xml. KeyCode::JIS_KANA also changes to Japanese and KeyCode::JIS_EISUU changes to English even if you don't have a Japanese keyboard.