For online,you can use my Google-TTS-Library-For-iOS to achieve your goal.
Offline iPhone TTS implementation is easy to do. You can see the details here.
There are many paid and free iOS TTS libraries are available .
They are ,
Free (Offline/Online)
- iphone-tts Note: read "HOW TO USE" section .
- TTSOverview-iOS
- flite-1.4-iphone
- Openears
- cmu.edu
- RJGoogleTTS
- VocalKit
Paid (Online)
- iSpeech iOS SDK (TTS and ASR)
- nuance Dragon-dictation
- Acapala
- ivona
- neospeech
