Why would that not turn into WDFGHGFDSASERT?

Because it's got a big list of n-grams and knows what words are more commonly used than others. It uses a predictive model to generate a list of words from your swipe, and then sorts that according to usage. It also continuously learns what words you use the most and prioritizes those. It picks the most likely word, but also displays a list of other possibilities you can tap. It's pretty slick.

Okay, so I grabbed my phone and tested it out. It...actually works. It's a bizarre method of text entry, but interesting nonetheless.

> It's a bizarre method of text entry, but interesting nonetheless.

And by bizarre you mean fantastic... It's even better in a language like French, where swiping means not having to type in the accents, whereas normally you'd have to do a long press of the letter and then select the accent you want...

You don't need to type spaces either and keyboards can be more compact as it's about the word shape rather than hitting a particular letter sequence exactly. Stock Android 4.1 version at least seems pretty forgiving provided I hit the correct first letter, a lot of weight in the algo appears to lie with first letter.

See also this for a similarly working, but different approach to the same thing:

https://www.youtube.com/watch?v=M9b8NlMd79w

Because the keyboard has a dictionary and can choose the most likely word you meant from your swipe waypoints

Clever programming.