Playing audio in call

Hi I'm new to this and I want to know exactly what I will need to complete my project.

Basicly I will call up the arduino and it will automatically answer and start playing wav files.

(I will record myself saying 0-9 and save each file as 0.wav, 1.wav and so on)

So when the arduino automatically answers my call, For example I want it to say 0, 6, 5 using the wav files I pre recorded.

How would I go about doing this and what shields would I need?

Thanks