Many language codes cause errors

[blackears]

I'm using the eSpeak python wrapper to translate some text into phonemes. I'm finding that many of the languages listed by backend.supported_languages() are not available. So while I can phonemize using en-us, both en and en-uk fail with the error message

Error: Python: Traceback (most recent call last):
  File "D:\dev\github.com\blackears\parrotLipsync\lipsync_scratch.blend\espeak_test.py", line 11, in <module>
  File "C:\Program Files\Blender Foundation\Blender 4.0\4.0\python\lib\site-packages\phonemizer\backend\espeak\espeak.py", line 49, in __init__
    self._espeak.set_voice(language)
  File "C:\Program Files\Blender Foundation\Blender 4.0\4.0\python\lib\site-packages\phonemizer\backend\espeak\wrapper.py", line 249, in set_voice
    raise RuntimeError(  # pragma: nocover
RuntimeError: failed to load voice "en"

Same with French. fr-fr works, but fr and fr-ca cause an error, even though both are listed in supported_languages(). I'd like to be able to create backends with common language codes, but I have no idea how to tell which ones are available. (My script must handle a variety of languages. so I can't just pick one that works and rely on it.)

This is a test script I've been using:

from phonemizer.backend import EspeakBackend
from phonemizer.punctuation import Punctuation
from phonemizer.separator import Separator
from phonemizer.backend.espeak.wrapper import EspeakWrapper

from phonemizer.backend.espeak.wrapper import EspeakWrapper
_ESPEAK_LIBRARY = 'C:\Program Files\eSpeak NG\libespeak-ng.dll'
EspeakWrapper.set_library(_ESPEAK_LIBRARY)

# initialize the espeak backend for English
backend = EspeakBackend('en')
#backend = EspeakBackend('en-us')
#backend = EspeakBackend('fr-fr')
sup_lang = backend.supported_languages()
print(sup_lang)
 
# separate phones by a space and ignoring words boundaries
separator = Separator(phone=' ', word=None)

result = backend.phonemize(["alpha beta gamma delta"], separator=separator, strip=True)
print(result)