valedictory speaker vs valedictorian

valedictory speaker and valedictorian both are nouns.

Word	Noun	Adjective	Verb	Adverb
valedictory speaker	Yes	No	No	No
valedictorian	Yes	No	No	No

As nouns, valedictory speaker and valedictorian are synonyms defined as:

valedictory speaker and valedictorian: the student with the best grades who usually delivers the valedictory address at commencement

valedictory speaker (noun)	valedictorian (noun)
the student with the best grades who usually delivers the valedictory address at commencement	the student with the best grades who usually delivers the valedictory address at commencement