A Catalan man I met in India had learned some Hindi while he travelled, and it was the amazing the difference. While the staff were always good, friendly and polite, they were extra friendly with this gentleman. And they used to bring him 'extras' at meal times, offer him ice cream, free this etc. It was amazing.

Note almost everyone we spoke to spoke English usually fluently. So one would think learning some Hindi would be unnecessary but it does pay dividends.

I think it always pays to learn some of the local language even if only while there. Words like YES and NO, THANK YOU, PLEASE, HELLO, GOOD MORNING, GOOD AFTERNOON (however it is said) etc go a long way. Often especially the NO. NO in swahili works far better than NO in English!