Bieber initially sang with a boy soprano voice , before his voice broke , as was evidenced during a performance of " Pray " at the 2010 American Music Awards . Sean Michaels of '' The Guardian '' described puberty as " the biggest threat to his career " at the time . Jody Rosen commented that Bieber sings with " swing and rhythmic dexterity " on his debut album , noting his tone to be " nasal "
2010 American Music Awards
American Music Awards of 2010
Justin Bieber