Mark Weinrib asks about a typical typo:
I am trying to find out how to autocorrect double-letter capitalizations. For example, if I spell office “OFfice” I want to automatically make the F into a lowercase f. Microsoft Office has a setting for this. I can not find one in OS X, so when I am in Mail or` in TextEdit it doesn’t autocorrect.
OS X does offer this setting system-wide as part of automatic spelling correction, and it works in all of Apple’s programs and is available in other apps that take advantage of it. This autocorrect will drop in what OS X thinks is the “correct” replacement as you type—it may sometimes be the wrong one if you’re using a specialized term or a special spelling. Generally, it’s the right choice.