That's funny, I'm using a touch keyboard now, and I can still spell correctly.
Not at any appreciable speed, I am fairly certain. Touch typing is fast, while swiping is slow. So slow that auto-completion becomes an important and integral part of swiping.
Some companies tried that with word processing for touch typists too (long before swiping was invented), and almost all typists turned it off. With touch typing, you could finish a word much quicker than it took to look at the suggestion and accept it.