Michael Wood concluded his documentary about India yesterday. And it was refreshing, although perhaps neither "patriotic" nor "politically correct" to hear him refer to Bombay and Madras rather than their modern names. Because, obviously, he was speaking in English.
Every language, or more generally every related group of languages, has its own characteristic sound. I do not refer to the obviously different vocabulary in every language, but to the distinctive rhythm of each. It is the way that you can tell what language a foreigner is speaking even when you can't identify any single word. It is why you know the muppet show chef is Scandinavian even though he is unintelligible.
The English cannot pronounce correctly. Don't even try. The modern name Kolkata sounds a half-hearted mess. Stick to Calcutta.