How do I change a time lapse video on m Iphone 5 back to normal speed?

Capture an experience with time-lapse. (iSight camera) Choose Time-Lapse, set up iPhone where you want, then tap the Record Time-Lapse Video button to start capturing a sunset, a flower opening, or other experiences over a period of time. Tap the Record Time-Lapse Video button again to stop. The time-lapse photos are compiled into a short video that you can watch and share.

If you already taken a Time Lapse video. You can only slow it down using image manipulating software.

Maybe using Photos or iMovie app on your iPhone:

Set the Slo-Mo section of a video. (iPhone 5s and later) Use the vertical bars beneath the frame viewer to set the section of the video you want to play in slow motion.

Problem is that it isn't continuously recording in time-lapse mode. Frame rate drops to 2 a second for a clip up to 5 minutes long. Over 5 minutes the frame rate is even lower. You might be able to slow it down, but the motion will be jerky.