TTS text to speech.
TTS (TXT) synthesizes speech from string TXT, and speaks it. The audio format is mono, 16 bit, 16k Hz by default.

WAV = TTS(TXT) does not vocalize but output to the variable WAV.

TTS(TXT,VOICE) uses the specific voice. Use TTS('','List') to see a list of availble voices. Default is the first voice.

TTS(...,PACE) set the pace of speech to PACE. PACE ranges from -10 (slowest) to 10 (fastest). Default 0.

TTS(...,FS) set the sampling rate of the speech to FS kHz. FS must be one of the following: 8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000. Default 16.

This function requires the Mirosoft Win32 Speech API (SAPI).

Examples:
% Speak the text;
tts('我会说。');
% List availble voices;
tts('I can speak.','List');
% Do not speak out, store the speech in a variable;
w = tts('I can speak.',[],-4,44100);
wavplay(w,44100);