Does anyone knows that if "speech to text" and "text to speech" api's used in Siri are accessible in IOS 5 or IOS 6 SDK?
I researched but couldn't find anything about it in documentation, so if thats not included in SDK are there any "Siri" quality libraries in market?
We've made an SDK for isolated words (or small phrases) recognition, CeedVocal SDK. We use it in our own app Vocalia. It's not free though (but there's free trial), more information at: http://www.creaceed.com/ceedvocal
You might also want to check out ispeech's text to speech and speech recognition APIs. They already allow you to include it in your apps without much trouble and actually are a bit better than what Siri has. Siri's big strength is the NLP, not so much the underlying speech tech.
Check out Openears at: http://www.politepix.com/openears I've used it experimentally and it worked great. It will recognize preset vocabularies very well. There is a slight pause of 1/2 second or so before it recognizes the word and it gets confused in an environment with a lot of voices (a crowded restaurant), but in a reasonably quiet setting I found it works great.
For speech recognition you can use OpenEars (http://www.politepix.com/openears/) which works offline and provide good accuracy.OpenEars is free to use in an iPhone or iPad app. Yes OpenEars handles Speech to Text function.
Siri is not available in API form yet, however, any UITextField or UITextArea can be dictated to using the built-in option for speech-to-text.
iOS 10 introduces a new speech recognition API -
SFSpeechRecognizer
.https://developer.apple.com/videos/play/wwdc2016/509/