Ever wondered why we say “tick-tock”, not “tock-tick”? Or ”ding-dong”, not “dong-ding”? “King Kong”, not “Kong King”? Well, it turns out it is one of the unwritten rules of English that native speakers know without even knowing.
The rule, called ablaut reduplication, states: If there are three words then the order has to go: I, A, O. If there are two words then the first is I and the second is either A or O. Mish-mash, chit-chat, dilly-dally, shilly-shally, tip-top, hip-hop, flip-flop, tic-tac, sing-song, ding-dong, King Kong, ping-pong.
Actually, there are a couple of small exceptions. Little Red Riding Hood may be perfectly ordered, but the Big Bad Wolf seems to be breaking all the laws of linguistics. Why does Bad Big Wolf sound so very, very wrong? What happened to the rules?
Well, adjectives in English absolutely have to be in the order: opinion-size-age-shape-colour-origin-material-purpose-noun. So you have a lovely little old rectangular green French silver whittling knife. But if you mess with that word order in the slightest you’ll sound like a maniac.
That explains why we say “little green men” not “green little men”, but “Big Bad Wolf” sounds like a gross violation or the “opinion (bad)-size (big)-noun (wolf)” order.
It won’t though, if you recall the first rule about the I-A-O order. That rule seems unbreakable: all four of a horse’s feet make exactly the same sound but we always say “clip-clop”, never “clop-clip”.
So, rule of thumb: if a word sequence sounds wrong, it probably is.