Earlier week I learned something new about the English language, which isn’t something I get to say often. It was this:
Consider the following common words and expressions: clip clop, tick tock, flip flop. All three of course are onomatopoeiac, replicating the sounds of what they describe: horses’ hooves, a clock, and the sound of flip flops on the ground respectively. When you think about it though, all four of a horse’s hooves make the same sound, as do both flip flops in a pair, and a ticking clock. Why then do we include two different sounds in each phrase, and why does it sound so weird to reverse the two parts (e.g. tock tick)? This is all due to an unwritten rule in English that, if you’re a native speaker, you’ve been following all this time without knowing it.
Reduplication is a common process in which a word is immediately repeated exactly (bang bang!!), with a single changed consonant sound (lovey-dovey, nitty-gritty) or a single changed vowel sound (the examples above, in addition to hip hop, tic-tac, tip-top and many more). We can’t just use reduplication willy-nilly though: there are rules involved. If there are three words (and a change in vowel sound), then they have to be in the order I, A, O (ding, dang, dong!). If there are only two words, which is more common, the first must be I, and the second is either A or O.
This rule is so strong that it can even override other ones, such as the similarly unwritten but universally-followed rule about adjective order. According to this rule, which was brought to a lot of people’s attention last year, the individual harassing the Three Little Pigs was the Bad (opinion) Big (size) Wolf. But, that would violate the I, A, O rule of reduplication, so we call him the Big Bad Wolf.
No-one really knows where this rule comes from. It might have something to do with the movements of the tongue in ancient precursors of European languages. It may be related to psychology and the mysterious reasons we find certain sounds more pleasing than others. All we really know is that we all follow this rule without being aware, and it sounds really strange when we break the rule!