This is the 7507th most frequent Spanish word.
isa
"Isa" is not a standard Spanish word; it may be a name or abbreviation.
It is used here as part of "vozisa," a colloquial play to imply 'unique voice.'
La vozisa que escuché es muy dulce.
The unique voice I heard is very sweet.
Here, "Isa" is used as a proper name or a nickname.
Me gusta la comida que prepara Isa.
I like the food that Isa prepares.
"Isa" could emphasize a region or elevated land metaphorically or contextually.