In my city, there used to be a language called Masematte. It was spoken mainly by Jewish itinerary merchants. It died out as most of Jewish population in my town was deported during WWII. However, it does left a trace in our local colloquial language. Words borrowed from Masematte such as Leeze(bike) and Jovel(good) are still used by young people these days. :)

I live in Belarus and Belarusian is our native language. But only a few people use it in everyday life here. Sad but true

The language of selflessness

Here in Bolivia, the least spoken language is English I think. I noticed when people come for tourism. They really need to know Spanish to move around the city, but things,etc..

Russian