Describe the bug

Hello I just started playing with the TTS library and I am running tests using the TTS Command Line Interface (CLI).
I was able to try capacitron, vits (english and portuguese) and tacotron2 successfully. But when I tried any of the xtts models, I get the same error that suggests I have yet to set a language option.

To Reproduce

I tried running the following and it issues the error

tts --text "Welcome. This is a TTS test." --model_name "tts_models/multilingual/multi-dataset/xtts_v2" --language en --out_path TTS_english_test_xtts_output2.wav

tts --text "Welcome. This is a TTS test." --model_name "tts_models/multilingual/multi-dataset/xtts_v1.1" --language en --out_path TTS_english_test_xtts_output2.wav

I tried these commands on multiple systems yet I get the same error
AssertionError: ❗ Language None is not supported. Supported languages are ['en', 'es', 'fr', 'de', 'it', 'pt', 'pl', 'tr', 'ru', 'nl', 'cs', 'ar', 'zh-cn', 'hu', 'ko', 'ja']

Expected behavior

No response

Logs

No response

Environment

- TTS installed from pip install TTS
- Linux OS

Additional context

My guess is that --language en is ignored and perhaps the xtts_v2 and xtts_v1.1 models are required to run in Python? I wanted to try a multilingual model through the command line interface (CLI) are there any missing steps I am missing here?

I was able to run bark using

tts --text "Welcome. This is a TTS test." --model_name "tts_models/multilingual/multi-dataset/bark" --language en --out_path TTS_english_test_bark_output2.wav