I became a better reader when I stopped sub-vocalizing (hearing the words in my head). I still do that when I read math. I tried not to do that when I read an expression today. I felt less confident about it, but it did seem easier. That lead me to suspect there are ways to make notation convenient (currently, it's a hindrance for me).
What are the best practices for reading notation fluently?
Not sure whether or not this applies to you but I find that many students have problems with maths because they don't fully realise that it all means something. Therefore they are trying to solve problems by memorising meaningless strings of symbols, and I think it's pretty clear that this is unlikely to be successful. My suggestion for these students is that they should vocalise what they are reading. To take an extreme and admittedly made-up example, if someone reads $$\{\,z\in{\Bbb C}\mid z=\overline z\,\}$$ as "squiggle-$z$-funny-sort-of-e-C-with-an-extra-line-on-it-vertical-line-$z$-three-horizontal-lines-with-another-$z$-under-one-of-them-final-squiggle" then their chances of success in mathematics are vanishingly small.
Hope this helps! BTW I have never actually used the term "vocalise" with my students, but it's a good one so I might steal it ;-)