How to make a normal video from time lapse recording?
Unfortunately, it is going to be difficult-to-impossible to make a recording look even somewhat "normal" from time-lapsed footage. Normal iPhone video footage is shot at about 30 frame per second, while time-lapsed footage varies between one and two frame per second, depending on the length. 

What that means is your iPhone only captured your subject about once per second, so if your subject was walking across the room (for example), they would have traversed about 3 feet in the time it took to capture each frame. All the motion in between is lost. 

Unfortunately, iPhone's time lapse mode does not record audio.

To adjust the speed of a clip, download iMovie for iOS (free):


With your project open, tap the video clip in the timeline to reveal the inspector at the bottom of the screen.
Tap the Speed button.
In the inspector, drag the slider to the left to decrease the speed. 


iMovie may not let you slow your footage enough to bring the speed down to normal. You will likely have to save the edited, slowed-down clip and repeat the process again until the speed of the playback appears normal. 

Unless there is very little motion in the video, I don't think you will be happy with the result, but no harm in trying. I hope it turns out good enough for your purposes!