"She talked like a waterfall!"

Translation: Hun snakket som en foss!

[PotatoSanta]

What is this saying? She talked a lot? She spouted nonsense? She spat when she talked?

[TCAC2]

It means she talked a lot. Quite common metaphorical phrase in Norwegian.

[loladesu]

So, a prettier version of the English "word vomit"? Or just chatty?

[Froscooo]

Just chatty. But very chatty.