I've met a few Garuds
They speak fluent Urdu and Arabic, some even speak fluent pashtun, they know about Muslim and islamic principles and practices etc etc.
The grammar and pronounciation are pretty damn similar.
This is our domain. Paras may need to train for weapons caching, evasion from surveillance, infil, exfil, developing contacts yada yada but once they're in the territory, good luck picking them out from the locals.
Hell,
@FalconSlayers knows Urdu too.
Punjabi, Bengali, Burmese, Tibetan, Nepali, we got it all covered.
Pashto, of course, requires actual training time. The closer you are to your home, the easier the language to learn. I'm okayish at speaking and reading Farsi/Dari and it almost feels like a dialect than a different language.
It's unrealistic to think anyone (even Green Berets) can speak fluent Mandarin. Most can't.
If you want an Indian guy to be fluent in Mandarin, hire a Chinese, send them to a civilian course or actually make them live in China.
I don't know how effective our foreign service's language school is but that could be an option too.
I bet my ass none of the Green Berets who don't come from a Chinese household can speak Mandarin beyond the basics.
The only US soldiers who can actually speak Mandarin functionally are the intel folks who go to their DLI course (2 years). Even with that much time, it must be terribly hard.
Tonal languages are horrible.