[ixtab]

The TTS checks that the language is english, and that the book allows for TTS. I have already found the place in the code. If you're curious, it's this snippet of code inside com.amazon.ebook.booklet.reader.plugin.tts.TTSProv ider$TTSAction:

        public TTSAction()
        {
            super();
            q a;
            boolean a = (a = TTSProvider.b(TTSProvider.this).oA().F()).K() && a.y() != 4 && TTSProvider.D(TTSProvider.this, a);
            setEnabled(a);
        }

yes, this is what the code looks like now - damn obfuscation.

So edit the book metadata - throw out the disable TTS flag (if set), and change language to english. The drawback is that this will probably also cause confusion with dictionaries.

I'm currently looking into various approaches to patch this.