Is preserving languages a good thing?

[Brian37]

Yes and no. Depends on context. 

The English language has certainly changed over the centuries. If you look at Middle Age English vs today, lots of it has changed. 

Language changes over time too. Words get added all the time to dictionaries. 

Language certainly is important to preserve from a archeological and history aspect. It is why we know what Ancient Egyptians thought. But outside historians and archeologists there are plenty of dead languages humans don't use anymore.

I don't speak ancient latin. And I am sure language will look different 10,000 years from now, if our species manages to preserve ourselves that long.

I meant primarily preserving endangered languages, I think it's clear from the context.

I can't put this down as an "either/or" proposition.

Times change, so in that context, no. 

History wise and archeological wise, yes, it should be preserved to learn from, but that does not mean it needs to be clung to.

Enough humans should care enough to document it historically yes, but times change as well.