Hi,
My name is Jobin Jose, CE of Jobin&Jismi IT Services LLP. I have read your requirement and offer you high quality app in android.
There is one obligation that how the phone should identify the voice of male/female. There are two solutions.
1. The user can switch on/off male/female voice while calling. In this case, we will program male/female voice samples.
2. We should program the phone to switch to male/female voice based on Vocal range or Voice type of the phone user. (There is a possibility of one to two second delay in this case).
We assume that we can complete this job within 200 -250 man hours of 2 year experience Android developer (A 5 year experienced android developer will manage this project, If awarded.
I would be happy to have chat/call with you on 06th April, 2015.
Regards,
Jobin.