I'll add the weird datapoint that I normally subvocalize, but that I've been aware since age 10 that I can also read prose while singing along to music that I'm familiar with.

I just tried doing this right now and my observations yielded that I appear to not subvocalize when I do this and that I seem to therefore speed up and lose a bit of comprehension/retention. Which is going to be fine in lots of contexts, but is worth being aware of.