phonology (n.)

word-forming element meaning "sound, voice," from Greek phōno-, combining form of phōnē "voice, sound" (from PIE root *bha- (2) "to speak, tell, say").

word-forming element meaning "a speaking, discourse, treatise, doctrine, theory, science," from Greek -logia (often via French -logie or Medieval Latin -logia), from -log-, combining form of legein "to speak, tell;" thus, "the character or deportment of one who speaks or treats of (a certain subject);" from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Often via Medieval Latin -logia, French -logie. In philology "love of learning; love of words or discourse," apology, doxology, analogy, trilogy, etc., Greek logos "word, speech, statement, discourse" is directly concerned.

"of or pertaining to phonology," 1800, from phonology + -ical. Related: Phonologically.