I want to use four language in my OS X system (English, Spanish, Chinese, and Japanese), and I know I can change the language with `⌘` + `Space`. However, I have a pathological hatred for switching with it, because it requires me to select from so, so many choices! I also know I can change it from the menubar on the right of the bar, but it's much more disgusting than the `⌘` + `Space` solution.

So I rather want to change it with easier shortcut, like the following:

* left `⌘` switches to English
* right `⌘` switches to Spanish
* left `⌘` + left `⌥` + `C` switches to Chinese
* right `⌘` + right `⌥` + `C` switches to Japanese.

I tried to use `Karabiner` (the descendent from `KeyRemap4MacBook`), but it doesn't work on the first attempt on Chinese, on which when I switches to Chinese, it remains English (the input source icon on the menubar changes, but the keyboard does not work). But for some reasons if I switch from English to Chinese to English to Chinese (two attempts), then the Chinese keyboard finally works.

So I don't like the idea of using `Karabiner`. So what is the better way to change the input source?