The support and inclusion of Hindi in the newest OS X 10.10 Yosemite appears to be available.
Within the setup and installation process of OS X various language options exist in the Installer;
and regional support for the computers to be set-up with a default language is possible. You
may find this to be the case, through a local authorized reseller, to buy an Apple product that
already runs in a local language. The OS X includes more than 20 languages, in the system
setup. The availability of matching keyboard input devices with a local language may vary.
•Multi-lingual Mac: recent language addition info
http://m10lmac.blogspot.com/
•examples where inference of Hindi support in Mac OS 10.10 appears in articles:
https://www.google.com/?gws_rd=ssl#q=Mac+OS+10.10+Hindi+language+supported
As of Lion OS X 10.7, there were 22 languages included in the system, via setup installation.
More have been added since. You may need to contact regional or local authorized reseller
of Apple products for specifics and availability of certain items there.
A historical overview, some details missing, can be read here:
http://en.wikipedia.org/wiki/OS_X
You could use the Locator page to find Country, then use City/country and product to see
the nearest authorized reseller and service businesses along with address & contact info.
•Apple - Find Locations - Country Selector:
https://locate.apple.com/country
The Locator can also be used to find non-Apple branded authorized regional resellers &
associated service companies; in some cases, they may exist but be difficult to find. These
usually show in the locate map, with phone number, street address & other contact info.
Hopefully this may help find the product & service you need.
Good luck & happy computing! 🙂