Chances are likely you’ve never heard of the term “ablaut reduplication.” It was new to me as well when a friend emailed a hard-to-read screenshot of a brief newspaper clipping.

Being a word person, of course I had to search around to learn a little-known rule about the order of vowels for two- or three-word phrases such as “ping pong,” “chit chat” or “big bad wolf.”

We’re all more familiar with ablaut reduplication than we realize because we use word pairs all the time, such as “jibber-jabber,” “knickknack” and “zig-zag.”

A mid-19th century Germanic word, ablaut refers to words that change form when a vowel is shifted. Reduplication originated in the late 16th century from the Latin word reduplicat, signifying doubled again. Translation: word phrases that repeat or copy and form a similar kind of word that suggests a “to and from motion,” or a changing state from one form or another, such as “tick tock.”

Here is how the ablaut reduplication rule works. If there are three words, the order of vowels is I, A, O, and if it’s a two-word phrase, the vowel in the first word is still an I, with either A or O for the other word. That’s why we don’t refer to table tennis as “pong ping” or the main character in “The Three Little Pigs” as the “bad big wolf.” It just doesn’t sound right, and the ablaut reduplication rule is the reason.

Naturally, when it comes to the English language, there tend to be exceptions or variations. The ablaut reduplication rule is referred to as an unwritten rule. There are five other reduplication rules: rhyming, exact, “shm,” comparative and contrastive.

Rhyming reduplication is easy-peasy to remember, as is exact reduplication, given it’s a word that repeats, such as “night-night” or “choo-choo.”

Yiddish roots influenced the shm-reduplication rule, which expresses indifference. like “fancy-shmancy.” Comparative reduplication indicates change by repeating the adjective, as in “her skin got paler and paler,” and contrastive reduplication is best explained with an example: “I’m awake, but I’m not AWAKE-awake,” meaning not really awake.

Ablaut reduplication is not the only rule in the English language that we didn’t know we knew. There is an unknown rule defining the order of how adjective categories are used to describe nouns that for now shall remain unknown.

Instead, I’ll leave you with the fun of identifying how many ablaut reduplication word phrases you can name. You can also run it by your family and friends; even children could find this entertaining. Okey dokey?

Writer, editor and speaker Cheryl Russell is a Laguna Woods Village resident.