TTS User Guide
1) will be fixed in our upcoming release
Thanks for finding 2. I'll push a fix. Thanks! On #2, this may just be an issue with what version Colab imports (so users not using Colab might not get the error with the current NeMo code, not sure?) Should be fixed now. If not, please open another issue.
Please note the TTS user guide quick start seems to have two issues (https://docs.nvidia.com/deeplearning/nemo/user-guide/docs/en/stable/tts/intro.html):

1) More easily solvable: spec_generator = SpectrogramGenerator.from_pretrained("tts_en_tacotron2") <- the variable should be named spec_gen to match the lines that follow

2) The last line:
sf.write("speech.wav", audio.to('cpu').numpy(), 22050)

This gives the error "RuntimeError: Error opening 'speech.wav': Format not recognised." I believe this is an error with soundfile, see: https://github.com/bastibe/python-soundfile/issues/203

EDIT: For issue 2, to fix this in Colab, simply create audio2 = audio.transpose(), which works. May just be an issue with the version of soundfile imported by Colab. 

