This is the 6456th most frequent Spanish word.
bulbuente
It seems "bulbuente" is not a standard Spanish word. It may be a typo or a regionalism.
Here, 'bulbuente' describes the bubbling and lively nature of the flowing river.
El río fluye bullicioso y bulbuente después de la tormenta.
The river flows lively and bubbling after the storm.
In this sentence, 'bulbuente' is used to describe the boiling state of the soup.
Una sopa correcta debe estar bulbuente antes de agregar los ingredientes.
A proper soup should be bubbling before adding the ingredients.
Here, 'bulbuente' metaphorically describes the lively and bubbly quality of the person's manner of speaking.