buddan-buddan 
In Appalachian speech, "buddan-buddan" is an onomatopoeia usually used to mock anybody riding or driving anything with a motor. But it can just represent the sputtering, uneven sound of a small engine-minibike, lawnmower, go-kart, tiller.
We used to ride a little Honda 50 that went buddan-buddan all over the neighborhood. Until my brother hit a moving car. After that, we had to ride a dented Honda 50 missing a headlight around the yard. Pronunciation
Meaning & Usage
- Small-engine sound (noun / sound-word)
Hear that mower? Buddan-buddan like it’s runnin’ on one cylinder.Yep, she’ll cut if you baby her.- Mocking imitation of an engine (interjection / tease)
Buddan-buddan!(said with a grin)
Origin
Oral Appalachian usage; a playful, phonetic way of imitating a chugging small engine. Likely evolved locally alongside everyday farm and yard machines, then passed down in families rather than written sources.
Notes
Most common in rural Appalachia and the South. Often doubled ("buddan-buddan") to mimic rhythm. Works straight for sound, or jokingly to deflate showy revving.
Say It Like a Southerner
Say it quick and bouncy: "buh-dun buh-dun." Keep the vowels short and let the second beat land a little softer, like a tired cylinder missing a stroke.