I know that there is no public API for the SIRI-Services, but is there an API for simple Speech-Recognition? So if I have a textfield and the user taps onto that textfield, a keyboard with the typically microphone button appears and if he pressed it the speech get recognized and transformed into a string object? Or is this button maybe presented by default?
There are many libraries availble. You can use any of them.
Hope it helps you.
NOTE:
if you download openears (which contains a sample project called "OpenEarsSampleApp") @efimovD mentions this
Check the code in view controller and you will see an array with possible commands. This thing detects commands! Not some talk. It listens and tries to compare what you've said with the words from array