Sorry if I was unclear, but that's the opposite of what I'm saying. It feels as if simultaneous keypresses are not working once I type faster than a certain speed because of the way double tapping is implemented.

I think I'd prefer tap and hold for the secondary character. Right now spelling is getting totally mangled no matter the technique of the user.

Since tap-and-hold has a longer delay, wouldn’t it be more suitable as a method for various extended characters in the multilingual versions? I will check whether there is any interference between simultaneous input and double-tap and take the necessary actions. Thank you for the feedback.