Phone Block question

I am considering an app that can receive an incoming text, translate that text to speech, record it and then make a phone call and play the recording of the text.

I would love it to run as a service, but I I don't think that is possible.  

The phone call once connected seems to disable all other sounds.  Is there a way around that?  It seems more a limitation of the phone rather than the programming.  

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 make a phone call and play the recording of the text.

unfortunately that's not possible using App Inventor, even for Android directly it would be a challenge, see for example http://stackoverflow.com/questions/26924618/how-can-incoming-calls-be-answered-programmatically-in-android-5-0-lollipop

The phone call once connected seems to disable all other sounds.  Is there a way around that?  

this is how Google designed it, you can't change that in App Inventor

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