Your friend can take a look at solutions from Acapela [0], SpeakUnique [1] or VOCALiD [2]. Not sure whether they have a solution for Android though.
I recently saw a video from google about a custom voice they created for somebody with ALS but I can't seem to find it online (Does anybody have a link?). Creating custom voices is not yet available on Android though. The latest iOS release (iOS 17) does support creating personalized voices.
ModelTalker [3] is a long-term (research?) project to create custom voices for people with speech disabilities. Their TTS seem to support Android so that might be another option.
I recently saw a video from google about a custom voice they created for somebody with ALS but I can't seem to find it online (Does anybody have a link?). Creating custom voices is not yet available on Android though. The latest iOS release (iOS 17) does support creating personalized voices.
ModelTalker [3] is a long-term (research?) project to create custom voices for people with speech disabilities. Their TTS seem to support Android so that might be another option.
[0] https://www.acapela-group.com/ [1] https://www.speakunique.co.uk/ [2] https://vocalid.ai/ [3] https://www.modeltalker.org/