[zgoat]

This can be dictated by circumstances though, I work in a situation where programming isn't the main value add of the work (but is necessary anyhow), so people tend to identify with their language and formally "switch" because there isn't time to work with / learn more than one or two languages max.

I've happily identified as a "Python programmer" while it was the main language I was using, and now more or less call myself a "Go programmer" after a similar switch. In less code-centric teams it's a handy way to identify where you are coming from.

Another reply here noted the time investment can lead to attachment, I find this true as well. When I decided to switch to Go for my next project, the only way to learn it was to put in some serious hours on the weekend and late into the evenings. You can't help but identify with something when you make that kind of effort towards it. All of the little cognitive biases and tricks with ego keep you invested enough to keep learning.