What does "all" mean here? Is it different between just "alone" and "all alone"?
Native speaker’s answer
Rebecca
"All" in this context means "completely" or "entirely". So "all alone" emphasizes that they are going to be completely alone and by themselves. "All alone" means the same thing as "alone", but "all" is used for emphasis and makes the meaning of "alone" even stronger. Ex: When I first moved to New York I was all alone. Ex: We should go talk to him, he is sitting over there all alone.