I also find it astonishing that I can feel like I had an entire sentence in my head without any of the words, and fluidly produce all of the words
as I say them, without having to search for them or consciously line them up. They're just
there, one after the other, like tokens waiting to be picked up. (LLM anyone?) I don't even think that my conscious brain knows exactly which words are going to pop out, say 5 words on. It seems to magically find each word as I speak, without having to pause or rebuffer.
I don't think that language is slowing me down. I actually think that my brain is full of shit and needs to run thoughts through checkers (lint, syntax, logic, fact). I think it makes the language center of our brains all the more magical. As you say, it all happens so fast, and yet it assembles and sanity-checks those raw thoughts as you crystalise them into words.
How many times have I started explaining something, only to realise midway through that I'm taking crap, or that I'm extremely fuzzy on some important detail. Or maybe I infer some important new fact or make some new connection for the first time, while talking about it?
Dogs have thoughts... but we can speak. And every time there's been an innovation in the storage, retrieval or communication of language (not raw thoughts), we've had a gigantic evolutionary leap forward. Isaac Newton was a genius. But when he took up the challenge of explaining the motion of the planets, I bet that not even he knew what he was going to end up with at the end, and I bet that he realised, discovered or rained out a whole bunch of things in the writing of it.
Something else I've wondered. How come my brain holds a million different facts, records of! historical interactions with others, and a pretty decent track of time (like, I know the time, day, month and year and what I did-or-didn't do yesterday), but my dreams are total gibberish? Like I was in a hotel lobby last night with a bunch of people I don't know, realised I'm wasn't wearing any pants, then paniced because my phone was in my pants, how would I call my wife? So I turn to my (deceased) sister and asked which room I'm staying in... If my brain is so good, how come it does crap like that when the conscious bit is switched off?
I would never assume that the data inside my brain, or the subconscious babble that counts for thought, adds up to a genius that is hindered by some clunky language. Very much the opposite.
Side note: all of this is the basis for my extremely strong view that freedom of speech is an absolute necessity for continued prosperity, science, democracy etc. If people are unable to turn their ideas into concrete language, and to do this together as a group, without fear, then they are unable to reason things out properly and make good decisions. I only feel like adding that because within my lifetime I have seen an erosion of the importance of that freedom, to the point where it's no longer possible to discuss mundane, everyday things, or to point out some obvious truth.