Tell me, are there any libraries that Ios SDK, with which you can add effects to the voice. That is necessary to make the voice of a speaker. that is something that is said in mokrofon, add effects horn and transmitted to the headphones (speaker)
Look into DSP, (Digital signal processing). This won't come easy as it does get rather complicated (ever heard of a Fourier transform?). Start by trying to make something react to audio first as you will learn a lot about how to do what you want to do.
tl;dr: there is no magic way to do this without putting some time into learning it.