Nepal's Kusunda language has no known origin and a number of quirks, like no words for "yes" or "no". It also has only one fluent speaker left, something linguists are racing to change.

At  present there are 7 109 languages, most of them – spoken.

All hiararchies of languages are built on vehicular languages, because regional languages are interesting only to their speakers. That;s why any attempt to substitute a regional language for a regional one is doomed to failure.