[ghaff]

GitHub and SO may be relevant directionally for languages that have some material presence on those sites. It's not unreasonable to think there may be a decline though, for a language still at #3 or so, the headline somewhat oversells.

But, yes, there are definitely limitations to GitHub and SO data. You'd probably have to do some primary survey research of the audience in question--e.g. large enterprises--to get better numbers for that audience. And, even then, my experience with trying to get some sort of handle on the amount of C code out there years ago was that few people really have a great grasp on lines of code (? an imperfect measure in its own right) of various languages in use in their organizations.

[tuxone]

A better data source could be online job listings. With the correct considerations that data may give you some insight on tech trends.

[ghaff]

Possibly. I'd have to study the data sources to have an opinion. I could definitely see it being a source for languages that you wouldn't necessarily expect your average Python or Javascript developer to know or casually pick up--and therefore would be certain to be explicitly called out in a job ad.