If you like having Siri available to answer a quick question every now and again but don't want everyone who picks up your iPhone to also have access to your personal assistant, there's an easy way to disable her from working on your iPhone's lock screen. This is also something you can do if you're always activating Siri accidentally in your pocket.
Siri makes it easy to call almost any contact on your iPhone with just a quick verbal command. I say almost because counterintuitive name pronunciations such as Caoimhe, which is actually pronounced "Keeva," will confuse the hell out of Siri. Luckily, there's a way to get Siri to understand pronunciations for the tricky names in your contact list ... it just takes a little grunt work on your part.