how do i set up speed dial on my iphone 5

There is no "speed dial" as such on iPhones. What you can do is take a telephone number you would like to "speed dial" and move it to "favorites" under the Phone app. One way is to open the Phone app, click "Favorites" on the bottom, then the plus sign in the upper right and add there.

To phone a favorite, simply open the Phone app, click "Favorites", then click the row containing the name and phone of the person you wish to call.

There is some speed dial technology in iphone 7 on the 5c. If you press and hold 1 on the dial pad it calls the voicemail. I'd imagine if they have it for that, then certainly there must be a way to add speed dial for contacts. If there isn't, then it would be a good add on.

The press and hold "1" to get voicemail is not an Apple or iPhone feature. It is a cellular carrier feature.

I completely disagree with your statement "If there isn't, then it would be a good add on." It is superflous to a feature that already exists on iPhone, namely, favorites.

There isn't any speed dial on an iPhone. The only thing kind of close is adding Contacts to your Phone>Favorites. Then select Favorites and tap the Contact you want to call.

Not sure how speed dial is any easier than tapping Favorites then tap the name of the person you want.

With speed dial, you have to remember who is programmed for each button as opposed to seeing their name.

Alsio, you can just press & hold Home then say "Call Bob"

I found a speed dial trick that works a treat in my car, the iPhone 4S is bluetoothed up to the car kit.

I press a number on the car number pad which represents the position of the number in favourites, then I press the dial button on the car kit.

Miraculously, the phone places a call to the number I punch into the car kit, no asking Siri, no unlocking, it just works, like pressing and holding three worked on a Nokia to ring whoever you had assigned to button 3.

I added a few extras to my favourites list, I stopped at 18 and every one of them dialled as expected. So you can now have more than 9 speed dials :-). OK you do have to remember who is assigned to which number.

Don't know if this is an undocumented feature of iOS 7 or the car integration kit (Mercedes E class saloon), like most things Apple, it just works :-).