I recognize this might push against the minimalism you're going for, but I might suggest having the next word, or even two words, off to the right and greyed out. What you're measuring is recognizing and typing the word, and most competent typists who want to lower error rates and gain speed are going to be fast enough already that they (we) can be recognizing the next couple of words while typing the one which is already centered.
A two-word lead would let me get up to speed, maybe that should be configurable but for the words I've seen while playing with it, probably two is just right.
Great site, I'll come back and use it as-is.
I usually go to https://10ff.net/ when I am looking to practice the whole typing flow.
This site looks like great fun as a member of the toolbox for making my Colemak more fluent!
170+@1m is impressive. I'm around 140-160@1m, ~230 burst, regular QWERTY.
https://pianop.ly/misc/typingtutor/
One thing I experimented with is giving you both a "total speed" and a "best 15 seconds" speed.
To calculate the WPM words with 5 letters are taken. To reach e.g. 80 WPM you'd have 150ms per character.
The application uses ~1000 most common english words and only gives you the next word once you've cleared the word in the calculated time.
The time is measured only as soon as you press the first key.
Give it a try.
Controls: [Space] or [Enter] to complete a word. [Esc] to move on to a next word
Click [wpm] to set your target speed. The default is quite low but you might still find words that you can't type within the time limit. Click [log] to see a log of your individual attempts.
How it was build:
No dependencies, single html file
Respects system preferences for dark them
Keyboard friendly (autofocus, tab & enter for settings, etc.)
Next up:
Using Service Workers to allow offline usage