No, Mostly we used language is English/Hindi.
You speak the language of the State in which you call.
If you don't speak this language, you can provide the necessary information in English/Hindi for instance. English/Hindi are the most used languages, in 36 states/UTs you can get assistance in English/Hindi.
In some states/UTs they can take your call to the emergency number in the language of the neighboring State/UT as well.
In Conclusion :
Basically there is no special language required when call by 112.