Translated Bengali Advertisements

All the advertisements that are made for the national audience are either made in English or Hindi. Then those advetisements are translated in local languages and aired in the regional channels. After coming to Delhi, my ear caught some sound bits of those adveertisements. Interestingly, I noticed something. I used to think that the Bengali translations are done in Kolkata. But recntly I realized that they must be done in Mumbai itself and the voice over artistes have to be from Mumbai. This is undestood only from the child voice over artistes as they speak in a heavy non-Bengali accent. This is because that is how they speak in their mother tongue Bengali since they are growing in Mumbai and not Kolkata.