In my experience, at least some aspects of the Indian English exists because we Indians often mentally translate what we want to say from our native language (which are plentiful) to English before it comes out of our mouth.
I don't imagine this is a uniquely Indian phenomenon – other non-native English speakers would be doing the same.
Even Irish people whose main language since birth is English do this. There's a verb in Gaeilge which does exist in English but is translated as "does be". Examples:
- He does be eating his breakfast
- She does be out walking the dog
It's the continuous/habitual form of to be, so the implication is that she does be walking the dog everyday, or regularly. He does be eating his breakfast everyday.
The interesting thing is that you'll meet Irish people who were never fluent in Irish - learned it in school, sure, but never spoke it daily - who still use this conjugation when speaking English.
In my native Cantonese (and this probably applies to a lesser extent to Mandarin as well), pronouns are inherently non-gendered, and when we speak in English we tend to randomly pick one (he/she) and thus occasionally get the gender wrong.
That said I think there are "levels" to so called "mental translation" -- I don't think I consciously mentally translate anything at all, but I guess sometimes the neural pathways or whatever are kinda repurposed/re-used even if there are some differences between languages.
I don't imagine this is a uniquely Indian phenomenon – other non-native English speakers would be doing the same.