is_language_supported() returning invalid results

[blackears]

I'm trying to create a script that can run on several different languages and would like to have a way to tell if Gruut is able to phonemize a particular language. Unfortunately, get_supported_languages() and is_language_supported() are returning results that are not accurate. If I do a fresh install of Gruut, these methods will tell me that Russian, Portuguese and Chinese are all available languages. However, if I use Gruut to parse these languages, they do not return any results. I have to specially install gruut-lang-ru for Russian to work and gruut-lang-pt for Portuguese to work. And there is not even a gruut-lang-zh to be installed, so I don't know why these methods are giving results that suggest that Chinese is a possibility.

Is there any way to check if Gruut can actually process a particular language?