"Dad, wait up" vs. "Dad, wait"

[milan2003_07]

In the film "Hone Alone 2. Lost in New York" Kevin's whole family were late for the plane. They all had overslept and had to rush to the airport in order not to be late for the plane.

In the airport building (in the terminal), while the whole family were running very rapidly towards the boarding gate, Kevin stopped on the way in order to change batteries in his father's camcoder. Then he had to speed up to catch up with his family.

While running (after replacing the batteries) Kevin was shouting: "Dad, wait up!", "Dad, wait up!".

What would be the difference if Kevin had had been shouting "Dad, wait!", "Dad, wait!".

Then Kevin was shouting: "Hey, guys, wait up! Wait for me!"

 

[jutfrank]

In practical meaning? Nothing.

https://www.collinsdictionary.com/dictionary/english/wait-up

 

[5jj]

The only difference that I can see is that we older speakers of BrE do not use 'wait up' in that sense.

 

[jutfrank]

To me 'wait up' sounds a bit American. I don't think it's used as much in BrE.

 

[SoothingDave]

We could also say "slow up" or "slow down" and they both have the same meaning.

 

[Skrej]

Similar phrases you might hear in this context are 'hold on', 'hold up, or 'hang on'.