As gē, 咯 is pure onomatopoeia — it almost always reduplicates as 咯咯 (cluck, giggle) or pairs with 吱 in 咯吱 (creak). Solo gē is rare; expect the reduplicated or paired form.
memory
Mouth radical 口 plus a sharp gē syllable — picture a hen's beak punching out short clipped sounds. Same clipped-beat logic in English 'cluck' and 'cackle'.
Left radical 口 — flags this reading as a vocal/animal sound. Hen-clucks, giggles, and creaks are all sounds the mouth (or a wood joint imagined as one) produces, putting 咯 in the same family as 哈 and 嘿.
Right phonetic 各 — gè → gē is a clean phonetic match (same initial g-, related vowel). This is the most transparent of the three 咯 readings, since gē sounds nearly identical to standalone 各.