Updated June 7th, 2019.
Did you know your Mac can do dictation? Starting with OS 10.8, it can. Go to the Apple menu, then System Preferences, then Dictation & Speech. The directions are right there in the preference pane. See below.
You can dictate in just about any program that lets you type: Mail, Word, Pages, Safari (try searching Google by saying what you want to search for). If you’re a lousy typist the Dictation feature is your dream come true. Even if you’re a great typist Dictation is a real asset. Try try try it!
Hint: tap the shortcut key twice to make the Mac start listening. Tap it ONCE to make it stop, when you’re done talking.