"AquesTalk TTS" is a Japanese Text-to-Speech (TTS) engine.
You can output Japanese sounds with various applications.
The voice "Yukkuri voice" is very familiar to YouTube and Nico Nico douga.
1) It starts automatically after installation from Google Play.
If it does not start, tap "AquesTalk TTS" from the application screen and start it.
2) Tap 'Voice' to select the type of voice.
3) If you hear Japanese voice by tapping "Play sample", it is OK.
4) Tap "Text-to-speech settings (system)" and specify "AquesTalk TTS" for the priority engine. You can also set the speech speed and voice height on this screen (Change the default language to Japanese temporarily).