[sapientiae3]

I’m convinced this is a result of typing on a keyboard - it seldom happens when I’m writing.

I think that after a typing for a while, your brain tries to introduce some optimization, i.e. while your one finger goes for the letter ‘t’ (my left hand), your brain queues up the letter ‘h’ for another finger on your other hand. Quite often, and possibly because I’m right hand dominant, the hand going for the letter ‘h’ gets there first. It usually happens with the same pairs of letters.

It would not surprise me if keyboards have introduced whole new kinds of dyslexia.

I have noticed this has crept into my writing occasionally - if I have been typing a lot - usually with the same pairs of letters. I will write the second one first, and then go back and insert the first one.