I actually have to get even more specific than this (at least prior to being diagnosed with ADHD in 2020 and getting Vyvanse for it).

If I need a mood boost or something to get my body "moving" in my seat and keep me from mentally wandering, I'll throw on stuff I really know and love. Usually I'm doing menial tasks or simple coding.

If I'm having a hard time focusing and need a distraction for some parts of my brain but not all of it, I have a "deathcore" (really more like melodic (tech) death metal) playlist where most of the songs sound very similar and you can't understand a thing the vox are saying.

Typically if I'm super tired AND need to block out the outside world but even hard to understand screaming won't cut it, I have to resort to either instrumental metal or LoFi hip hop beats to study to.

If I'm currently listening to music, I really only do a full stop/pause to focus if I notice I've run a breakpoint three times and have no idea what I've been stepping thru, or if I'm trying to refactor or write a fresh, new logic flow and just can't get my brain focused enough to "check it" for all possible paths. That's when I cut the feed, double-time my focus, and once I'm convinced it's "safe" I can hit play again.

Brains are weird and finicky I tell ya.

Do you notice your musical tastes at a given moment are modulated by Vyvanse levels? I find as I ratchet up the dose, or get very deeply focused on a task, the complexity of the music I listen to goes down. Morning, before the meds kick in, I like high-complexity high-energy stuff: eurobeat, electroswing, hard bop. That gives way to psytrance, then house, then techno, with high-tech minimal being my go-to when I am really firing on all cylinders. Then into lofi, downtempo, ambient, then silence for when I'm overstimulated.

For me, not being a native English speaker, it "feels" much easier to listen to music with English lyrics while working effectively on other cognitive tasks like coding, compared to listening to music with vocals in my native language.

On the other hand, there are several other factors, like how tired I am, how hard the foreground task is etc., so it is hard to pin-point it specifically to the lyrics language.

This 100%. I don't speak Spanish, but my god, Latin pop just gives me the flow.

For me it's how long I've been doing it.

If I've just started both are probably going to be good results. If I'm 4 hours in the music one will probably do better because I've not wandered away from my desk distracted by a shiny pen.

I've found for this reason I can never listen to new music I'm excited about when coding (i.e. a new album release by an artist I like), but I can listen to the radio and music I'm already familiar with without an issue.

Same for me. I can't code as effectively with lyrics in the music. Postrock hits the sweet spot for me.