SpeakKing is an app that uses the TTS engine to enter texts that are then converted into language. Then you can send your audio files (which are only stored temporarily) via WhatsApp. The best sayings can be saved in a list, with the G button you can generate sayings if you have no ideas. With the Read-A website feature you can read websites aloud.
Link to the Appstore:
https://play.google.com/store/apps/details?id=com.wirklich.ichspreche