Simplify the following text for a Grade 9 native English-speaking person.
Original: In music , an ostinato ( derived from Italian : `` stubborn '' , compare English : obstinate ) is a motif or phrase which is persistently repeated in the same musical voice . An ostinato is always a succession of equal sounds , wherein each note always has the same weight or stress .
Simplified: The word `` ostinato '' is related to the word obstinate .