can I change language in UnityEngine.Windows.Speech?

I’m very interested in new api UnityEngine.Windows.Speech and this quality is good.

I want to use dictation function in Japanese and English.
But I cannot find the way to set language (en-US, ja, and so on).

Is there a way to change language in runtime?
Or I can change language if I use some asset or develop plugins?

You may get more info there :

Some languages require to be added and some are simply not available.

It depends on the operation system language.
On my own computer, which has an English system, only English could be recognized.
On another one, which has an Chinese system, both English and Chinese could be recognized.