I've seen plenty of people in the middle that didn't get formal training, but instead developed patterns based around clusters of keys. They may use more than t

I've seen plenty of people in the middle that didn't get formal training, but instead developed patterns based around clusters of keys. They may use more than two fingers, but they have no concept of the home row. In fact, I've been asked by people who type fairly often what the little bumps on the 'f' and 'j' keys are, which tells me that they most likely didn't learn to type properly. My 5yo can "type" by hunting and pecking, and he's actually getting good enough that he doesn't get frustrated trying to type simple words (he likes looking up words at the library computers). My 2yo, however, knows his letters, but I don't think he really understands how keyboards work. Personally, I'd say that someone can type if they can use a keyboard productively and have some means of speeding up entry besides looking at every key until they find the one they want (most people know vaguely where there keys are, even if they can't touch type).