syllable vs linguistic unit

syllable and linguistic unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
syllable	Yes	No	No	No
linguistic unit	Yes	No	No	No

As nouns, linguistic unit is a hypernym of syllable; that is, linguistic unit is a word with a broader meaning than syllable:

syllable: a unit of spoken language larger than a phoneme
linguistic unit: one of the natural units into which linguistic messages can be analyzed

Other hypernyms of syllable include language unit.

syllable (noun)	linguistic unit (noun)
a unit of spoken language larger than a phoneme	one of the natural units into which linguistic messages can be analyzed