It is hard to assess what the most popular programming languages are because there are multiple ways to measure them, but none of them are perfect (i.e., repositories, lines of code, occurrences in job offers, etc.). For example, if you work with embedded systems, C is very popular, but if you work on the web, the story is very different.

One interesting measurement of popularity of a language is the questions related to the language. Stack Overflow features questions and answers on a wide range of programming languages and compiles a list of the most popular tags with total, today, and this week breakdown.

This data is a nice proxy for how popular the different programming languages are.