What's the difference between "go on ahead" and "go ahead"?

Native speaker’s answer
Rebecca
"Go on" and "go ahead" have similar meanings. "Go ahead" is used to urge someone to go forward and do something, whereas "go on" is used to continue an action that is being done. Ex: Go ahead and write your name on the paper. Ex: Go on, try it again. You'll succeed this time. Thus, the combination of "go on" and "go ahead" to make "go on ahead" means that someone is being urged to continue and go forward with something. Thus, there isn't much of a difference between "go on ahead" and "go ahead," as both urge someone to go forward and continue onwards. Usually, it is used to suggest to someone to move forward in the literal sense. Ex: Go on ahead without me. I'll meet up with you guys later. Ex: You can go on ahead. I will be a little late to the meeting.