It’s a specific linguistic feature called „ablaut reduplication”! English, and many other languages, typically follow a general pattern of high/front vowels to low/back vowels, usually along the lines of I->A->O. Tick-tock, splish-splash-splosh, zig-zag, etc! There are other forms of reduplication as well, such as rhyming (artsy-fartsy), exact (aye-aye), and even shm- reduplication (fancy shmancy— I think this comes from Yiddish influence).

15

2 syllables followed by one is more familiar Thinks of a drum’s “ba-dum tsss”

4