[AC Question]

If there was a deaf person with a smart phone listening a person could talk into mic and the phone would listen and text to the deaf person to read.

[B. Diddy]

Welcome to Android Central! Are you talking about two people communicating face-to-face, or remotely? If face-to-face, try Virtual Voice.

[Rukbat]

As someone who nearly is (>100db loss@4KHz), if the person is only deaf (not mute - lost his.her hearing late, so can speak), talk to text. It's a lot easier reading text than hearing silence.

However, most deaf people who aren't purists can read lips, at least a little. (I never took any lessons, but I can understand someone a lot better if I can see their lips when they speak.) So if they have any hearing left, no phone at all is probably best, because there's going to be a delay between the speech and the text, so the whole lip-reading advantage is lost (and it's a great one). I watch closed caption on TV if the sound isn't completely clear (and brilliant - biased to the high frequency end), but I lose the ability to lip-read, because the caption is out of sync with the picture.

For someone born deaf, probably none of this applies.