Kotlin is widely popular, official language for one of the two dominant mobile platforms. It accounts for 0.37% of all search results gathered by TIOBE. Meanwhile, languages on the first 4 positions account for more than 50% of hits. Languages like PHP or Go, which you can still call pretty popular are on the order of 1-2 %.

It's completely subjective. The objective metrics (if web search are them, which is kind of dubious) tell us that whatever-language-you-like is probably orders of magnitude less popular than Fortran. The "real" popularity that you experience - how big the community is, how many packages are published, how many success stories are there - heavily depend on where you are, who you know, and what you want.

The index: https://www.tiobe.com/tiobe-index/