The thing about accents is that they are easy to understand for people coming from languages with the same way or similar of speaking, ie french have an easier time understanding English spoken by a french than if it is spoken by an Indian. What I'm saying is not that one way or the other is superior, but that it is different for different people with different language baggages.

This can be used to make yourself easier to understand - change your accent to match the person you are talking with.

I don't find this to be true at all. Maybe it's not the hardest, but it's certainly not easy for me to understand Indian accents.

As an Indian myself, this has, variously, confused, amused and annoyed Indians speaking English to me. Unfortunately I don't speak a word of any Indian language myself.

There is no universal metric of what makes one accent easier to understand than another.

For years, literally years, I thought my Indian coworkers, generally from Bangalore or Chennai, were using 'devil up' as a turn of phrase that had caught on in India but that I wasn't familiar with. Meaning something like 'come up with'.

Develop. They were saying develop.