sound structure vs syllable structure

sound structure and syllable structure both are nouns.

Word	Noun	Adjective	Verb	Adverb
sound structure	Yes	No	No	No
syllable structure	Yes	No	No	No

As nouns, sound structure and syllable structure are synonyms defined as:

sound structure and syllable structure: the admissible arrangement of sounds in words

Other synonyms of sound structure include morphology, word structure.

sound structure (noun)	syllable structure (noun)
the admissible arrangement of sounds in words	the admissible arrangement of sounds in words