How can MP4 voice be converted into other spoken language? Example EnglishLanguage.mp4 into ArabicLanguage.mp4.

technically speaking, it should be done in 3 steps:

1- convert the english voice into an english text. (play the mp3 next to an android phone with a Speech-to-Text App or any equivalent).

2- translate the english text into arabic text (using google translate or a help of a bilingual person)

3- use an automated arabic reader app to read the arabic text (an arabic person would be much efficient to do so).

This usually takes a couple of hours to complete. results with technology, however, are hot as fancy and clean as a result of a bilingual person doing it!

Cheers

I agree with the answer been added by Ali Al Mahfoodh