My nibling is producing real, actual words! …mostly. Like most toddlers, the quality of production leaves something to be desired. Teepee, for example, comes out more like “peepee,” and coffee sounds more like “cocky.”
Obviously, the parents are having a great time, and I’m dusting off my background in phonology to analyze every single word they say.
It’s a fairly common stage in language development: children go through phases where they consistently replace the consonants in a word (the “target form”) with one from elsewhere in the word. This practice is called consonant harmony, and it was very intriguing for linguists in the 90s because it rarely happens in adult languages, except when the consonants are right next to each other (e.g. pronouncing input as “imput”). On the other hand, vowel harmony — where all the vowels in a word become the same — is a pretty common process across the world’s languages, even when the target vowels are separated by one or more consonants.
This observation is a Big Deal for linguists who believe that child language never deviates from the possible permutations seen in adult language. One of the key ideas in generative grammar is that, even if children are making lots of mistakes as they acquire their language, the grammatical choices they are making actually correspond to completely valid possibilities in some other language. A kid who says “Want cookie” is not following the rules of English (which requires a subject), but is perfectly fine in Spanish.
So, if a child says “peepee” instead of teepee, and that kind of change doesn’t happen in adult languages, that’s pretty dang interesting.
What’s going well
They have successfully identified and produced lots of important phonetic features: they know that the /p/ and /t/ sounds are both produced without vibrating the vocal cords; they know that /p/ and /t/ should be followed by a small puff of air (= aspiration) when they appear at the beginning of a word; and they know that both of these sounds are the result of fully preventing air from escaping the lungs for a split second (= stop consonants), as opposed to only partially limiting airflow as you would in a sound like /f/.
In fact, the only difference between /p/ and /t/ is that one is produced on the lips, while the other is produced with the tongue behind the teeth.
For a long time, everyone more or less assumed that these supposed speech errors were random, the result of children being unable to perceive or produce the subtle distinctions between sounds of the same category (i.e. stops).
However, as I’ve mentioned previously on this blog, it’s not true that babies can’t hear the differences between sounds. They’re actually really good at it. More counterevidence comes from the “fis” phenomenon, which was a study in the 60s where researchers showed a toy fish to a child who consistently “fis” instead of fish. When they asked him, “Is this a fis?” the child answered no, rejecting the adult’s mispronunciation. This is further evidence that the ability to perceive sounds precedes the ability to produce them.
This probably means that whatever goes awry happens somewhere in the production process: that is, the child has a mental representation of the word teepee in their head, but something gets jumbled up when they try to coordinate all the muscles needed to produce the word.
What’s interesting, though, is that there seem to be fairly consistent rules governing child consonant harmony. The fact that these rules exist is a testament to just how much children already know about the language(s) spoken around them.
Why doesn’t “teepee” end up as “teetee?”
Let’s take a quick dive into linguistic theory. Optimality Theory, proposed by Prince and Smolensky in the early 90s, is used in phonology to explain why certain sound alterations occur in a given context. The idea is that that there are underlying “rules” that everyone has in their heads, ranked in order of importance. Higher-ranked rules cannot be broken, whereas lower-ranked rules can be broken if there is no other choice. The ultimate goal: produce a word that is as close to the representation in your head as possible.
Lots of these rules target not just one sound, but a group of sounds that share a feature (such as place of articulation). When we group the consonants in question according to where they are produced, then we have the following categories.
Name | Place of articulation | Stop consonants |
Labials | The lips | p, b, (m) |
Coronals | The tip of the tongue | t, d, (n) |
Velars | The velar ridge | k, g |
An example of a rule that contributes to consonant harmony could be something like “Preserve all labials in the target word.” When a child then cannot stay true to the adult form of the word (for whatever reason), then they might refer back to the hierarchy of rules to decide which consonants they should prioritize.
Once they decide which segments can be changed and which ones have to stay the same, they can transform the word in some way that makes it easier to produce. This is a topic that I looked at for my Master’s thesis, so I can tell you firsthand that lots of children prefer to simply omit the challenging sound(s) altogether. This is why spot might become “pot,” or green might become “geen.”
Another option, of course, is to repeat a sound that is already available to you, especially if they share some phonetic features with the sound you want to (but can’t) produce. This is where consonant harmony may occur.
Since kids show different orders of preference for labials, coronals, and velars at this stage, the segment they tend to preserve can show us which consonant types they find most important (or maybe just easier to pronounce). This, in turn, can give us a hint about the ranking of rules in their head at any given stage. It’s time to analyze some data!
Looking back at “peepee,” it seems like labial consonants (/p, b, m/) outrank coronals (/t, d/), because the /p/ sound is what remains. Based on this information, we can make some predictions about how my nibling would pronounce other words at this stage:
- Potty > “poppy”
- Table > “babu” (/l/ is a whole other can of worms, so just go with me on this)
- Tuba > “buba”
- Boot > “boop” or “boo,” depending on whether deletion or assimilation is preferred at the end of a word
Pesky vowels
Now we have our first set of predictions, but they might need to be adjusted as we get more info. Where do velars (/k, g/) rank in comparison to labials and coronals?
Again, we can determine the order of priority based on how certain words are pronounced. Luckily, said nibling is in the middle of a vocabulary explosion and has given us two pieces of data to work with:
- Doggy > “goggy”
- Digger > “dadu”
Uhh… what gives?! In doggy, the /g/ stays, but in digger, the /d/ stays! There is no preference — it’s all just random after all!
This is the fun of analyzing linguistic data: just when you think you have a working hypothesis, something comes along to throw you off course.
You might be happy (or disappointed, if you were rooting against me) to know that there is a potential explanation for these two data points, and it has to do with the phonetic environment — that is, the other sounds that are occurring around the consonants in question. In our case, I suspect the first vowel is the culprit.
The /o/ in doggy is produced toward the back of the mouth, quite close to the velar ridge. On the other hand, the /i/ in digger (or the /æ/ in “dadu”) is articulated toward the front of the mouth. So, it seems plausible that in words featuring a front vowel like /i/, the coronal sound might be preserved, whereas in words containing a back vowel like /o/, the velar sound wins out. Let’s make some more predictions based on this hypothesis:
- Kitty > “titty” (…it’s what the science dictates, okay?)
- Taco > “kako” (according to American English vowels)
- Gouda > “duda”
Since we only have, like, three words to work with at the moment, it’s hard to say for certain whether the vowels would also have an impact on consonant harmony in words containing a labial consonant. If the vowel has no impact, then we can assume that the labials would win out over velars. If the vowel does have an effect, then we can assume that front vowels would trigger labials, while back vowels would trigger velars.
A few more predictions:
- Piggy > “pibby”
- Copper > “kako”
- Bugle > “bugu”
- Baggy > “babby”
As an aside, it’s very hard to come up with words that a baby might know that also have a (roughly) CVCV structure. So please excuse the ridiculous examples above.
How is this useful?
Sometimes it’s just nice to be reminded that your child is actually supremely intelligent and already pretty adept at this “language” thing. They’ve laid a foundation in their native language(s) and know how it should sound, the implementation is the only problem.
You can also start to appreciate the steps that they take on their unique language journey. Instead of just waking up one day as a fully competent communicator, they make small strides every day that all eventually add up to adult competence. It’s cool to observe the process.
Or maybe you’re just like me and you love finding patterns in everything and solving puzzles. That’s also a perfectly good reason to learn anything. If you’re bored with the monotony of childcare one day, you can always whip out a notebook and start trying to figure out the patterns in their speech errors.
Until next time!