Well if they r from Southern part of India, There are 4 different languages from 4 different states
State Language Greeting
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Karnataka Kannada Namaskara
Andhra Telugu Vandanam
Tamilnadu Tamil Vannakkam
Kerala Malayalam ???
Of course from each of these states u can find some more Sub Dialects of each of the languages.

If he/she is from Bangalore, then in all probability he/she will understand any of the above 2 languages including Hindi, English