Out of the blue, my Pearl changed the way it dealt with my typing. At first, I would see variations on the letters I typed. One day, it changed. I was then able to hit a key once or twice and get either the first or the second letter on the key.

Now, again, out of the blue, I am back to the original typing protocol. What happened and how can I go back to the ability to hit a key once or twice?

it is calls Suretype and Multitap.

You can enable it using the Full Menu or press and hold the * for a couple sec.