What does "tumble up" mean?
"...children were not growing up or being brought up, but were tumbling up."
In this sentence, what does "tumble up" mean? I know the word tumble means "fall" quickly and I assume the writer is trying to repeat "up" 3 times, but I am having a hard time imagining the movement of "tumble up". Could you please help me understand? Thank you!

Question

Answer

"Tumble up" would imply making a number of mistakes, one after the other, in one long chain of mistakes, until people are legally an adult (21 years old).   It is a play on words to create of picture of someone stumbling through life on their way to adulthood.
The mistakes would be due to the fact that no heed is being payed by the parents with regard to what a child really needs to grow up.