UNESCO currently lists 2473 languages in their world atlas to be "in danger":
While there is no real equivalent view in terms of programming languages,
you can still derive your own conclusion from the different popularity indexes
that are usually published at the beginning of a new year.
One is called the "PopularitY of Programming Language" index - simply PYPL. It is based on Google Trends and measures how often programming language manuals are being searched for at Google. It lists C# as the biggest winner in 2012 naming it "language of the year" showing an increase of 1.8% to a total share of 10.1% in 2012:
Well, if you don´t believe that much in swarm intelligence or what the makers
of PYPL call it "collective wisdom", there is another well known index:
TIOBE tries to determine the number of skilled developers using each language based on searches on different platforms like Wikipedia, Amazon, Youtube and others.
While you find some different results here, you still recognize a lot of well known programming languages. The list goes down to position 50 with a measured share of 0.158%. And then there is an enumeration of another 50 programming languages with rather exotic names like "Fantom", "Gambas" or "Groovy" that probably most software developers never ever heard of before.
Are they "in Danger"? We don´t know. But what we know for sure is that it makes sense to stick with at least the top 100 of listed languages for business applications to act strategically and make sure a community is still around in a few years.