Somewhere around the first birthday, many toddlers begin delivering speeches. Not words, exactly — something stranger and more wonderful. Your child fixes you with a serious look, gestures at the window, and produces a long, fluent stream of pure nonsense: dabidoo ba NEH neh, badoo? The pitch rises at the end. There is a pause. You are, apparently, expected to answer.
Parents describe it the same way almost every time: it sounds exactly like talking, except there are no words in it. Some worry it means their child is behind. Most just wonder what on earth is happening. What's happening has a name — expressive jargon, or jargon babbling — and it is one of the most revealing stages in all of language development. Your toddler has learned the music of your language before the lyrics, and is performing the whole score from memory.
The tune arrives before the words
Language has two layers. There are the segments — the individual consonants and vowels that make cup different from cap — and there is the prosody: the rhythm, stress, and melody that ride on top of them. Prosody is the part you can still hear through a closed door, when the words themselves have blurred away. It's how you know the muffled voices next door are having an argument, or telling a joke.
A womb is, acoustically, a closed door. The fine detail of speech doesn't survive the trip through tissue and fluid, but the melody does — and babies start learning it before they're born. In a study published in Current Biology in 2009, Birgit Mampe and colleagues analyzed the cries of French and German newborns just days old and found their cry melodies already differed in ways that echoed the intonation patterns of the language around them — French infants tending toward rising contours, German infants toward falling ones, mirroring the prosody of each language.
So by the time your toddler stands in the kitchen orating in fluent gibberish, they have been studying the melody of your speech for well over a year — longer than they've been alive. Jargon babbling is that melody, finally performed out loud. The sentences are empty, but the intonation is nearly perfect: the rise of a question, the flat authority of a statement, the little uptick that means right? It sounds like talking because, prosodically, it is talking.
From "bababa" to speeches
Jargon doesn't appear from nowhere. It's the last stop on a road researchers have mapped in detail. Around six to ten months, most babies enter canonical babbling — those famous repeated syllables, bababa and dadada, which is the mouth practicing the basic engineering of speech: pairing a consonant with a vowel and timing the jaw. Then comes variegated babbling, where the syllables start to vary — badigu, mabata — as the child mixes and matches sounds.
Something else happens along the way, so gradually it's easy to miss: the babble starts to sound like your language. The developmental psycholinguist Bénédicte de Boysson-Bardies and her colleagues found that the babbling of infants raised in different language environments drifts toward the sound qualities of the language around them — the vowels, the rhythms, the favored consonants. A baby babbling in a French-speaking home does not sound quite like a baby babbling in a Cantonese-speaking one. Babble, it turns out, has an accent.
Jargon is what you get when variegated babbling puts on the full prosodic costume: long strings of varied, native-flavored syllables, draped over sentence-shaped melodies, aimed at another person. It typically flourishes from around ten to eighteen months — which means it usually overlaps with first real words rather than preceding them.
What all that gibberish is practicing
It's tempting to hear jargon as noise — charming, but contentless. Listen closer and you'll notice it's doing serious work on everything about conversation except vocabulary.
It practices turn-taking: your toddler talks, stops, looks at you, waits. It practices pragmatics — the uses of speech. There is complaint jargon, story jargon, question jargon, phone-call jargon (often delivered while holding a remote control to one ear). The linguist Michael Halliday, closely documenting his own son's development, showed that children in this period often use consistent invented vocalizations with consistent meanings — a personal protolanguage of what researchers call protowords — before they command any conventional words at all. A particular nana might reliably mean I want that; a particular mm-nng might mean look at this. The sounds are invented, but the system — sound paired with stable meaning, aimed at a listener — is already language.
In other words, your toddler has assembled the entire frame of a conversation: the melody, the turns, the intentions, the eye contact. The only missing piece is the dictionary. And the dictionary is precisely the part that can't be rushed — words have to be collected one at a time, from the people who use them.
Why words and gibberish live side by side
A common worry: my toddler has real words — why do they still spend half the day talking nonsense? Some parents even fear the gibberish is a step backward.
It isn't. Through the second year, most children produce mixed jargon: real words embedded in a stream of babble, the way a lone recognizable landmark floats past in fog — dabidoo ba DOGGIE badoo neh. This coexistence is expected, because saying a real word and carrying a melody are different kinds of effort. A true word requires retrieving a specific sound pattern and executing it precisely; melody can be produced almost for free. When a toddler has something long and urgent to communicate but only a handful of expensive words, jargon is the sensible engineering solution: keep the sentence's shape and emotional content, and drop in real words wherever they're affordable. As vocabulary grows, the fog thins. The words gradually crowd out the filler, and the gibberish quietly retires — usually without anyone noticing its last performance.
How to answer a speech you can't understand
Since jargon is a bid for conversation, the useful response is to have the conversation. You don't need to decode it — you need to keep the rally going. Answer the intonation: if it sounded like a question, answer it ("You think so? I think so too."). If it sounded like a grievance, sympathize. Add a real word where you can guess the topic — if the speech was delivered while pointing at the dog, "Yes — the dog! He's sleeping." — because a word offered at the exact moment of shared attention is a word in its most learnable position.
What helps less: asking your toddler to "say it properly," or responding with silence because you didn't understand. The child isn't testing vocabulary; they're testing whether talking works — whether making these sounds at a person reliably produces a response. Every time it does, the whole enterprise of speech gets confirmed as worth the effort.
When gibberish deserves a closer look
Jargon in its natural habitat comes bundled with other signals: pointing and gestures, response to their own name, obvious understanding of familiar words, eye contact and back-and-forth. Alongside those, gibberish is a milestone, not a warning.
It's worth a conversation with your pediatrician or a speech-language pathologist if the jargon arrives without that bundle — little pointing or shared attention, little apparent comprehension — or if, by eighteen to twenty-four months, no true words are emerging within it. Early check-ins are low-cost and often simply reassuring; when support is needed, earlier is easier. But for most families, the fluent nonsense filling the kitchen is exactly what it sounds like: a child who has mastered everything about talking except the words, and is closing that last gap in plain sight.
The lyrics come one at a time
If jargon proves anything, it's that toddlers don't learn language from the outside in — they learn the tune first and fill in the lyrics word by word, in short, warm exchanges with people who answer them. That's the idea behind Acorn: one three-minute session a day for ages one to three, built around a handful of first words offered clearly and repeatedly — small enough to fit inside a toddler's real attention span, and designed to hand you words at the moments they're easiest to catch. No ads, no upsells; just a quiet daily habit for the season when the speeches are still mostly melody. If your kitchen orator is ready for a few more lyrics, you can try it at acorn.lumenlabs.works.