I've never heard anyone that read manga say 'main-ga'. And yes, there's a huge difference in the Japanese mispronouncing English words because they've never had to move their mouths/tongues in that way and just ignorance. I'm not trying to really insult anyone that says 'main-ga', but if you know the right way to say it and are capable of such, why continue to mispronounce it?

Because it's an "Americanism." :rolleyes:

Oh, of course! I get it now. Everything is better.