AP® Psychology · Unit 3 · Topic 3.5
Stages of Language Development
Language develops in a fixed universal sequence—cooing, babbling, one-word speech, telegraphic speech—and errors like "goed" reveal a child applying grammatical rules, not just repeating memorized words.
Every infant, regardless of the language they'll eventually speak, moves through the same early stages on roughly the same timeline. Around 2 months, cooing begins: soft vowel sounds like 'ooh' and 'ahh'. By about 4 to 6 months, babbling starts, repetitive consonant-vowel sounds like 'bababa' or 'dadada', using sounds from every language, not just the one spoken at home. Around 12 months, children hit one-word speech (holophrases), using a single word like 'milk' to mean an entire request. By 18 to 24 months, telegraphic speech appears: short, stripped-down phrases like 'want cookie' or 'daddy go', missing small connector words but carrying clear meaning, like a telegram.
The deeper story is that language learning is rule-based, not just imitation. A child who says 'goed' instead of 'went' never heard an adult say that word. They heard 'went' repeatedly. But somewhere along the way they extracted a general pattern: add '-ed' to make past tense. Then they overapplied that rule to an irregular verb. This overgeneralization is actually a sign of progress, not regression; it shows the child has moved from memorizing individual words to inferring and testing an abstract grammatical rule, something no simple list of heard phrases could produce.
This rule-extraction connects directly to the unit's bigger theme: a developing mind isn't just absorbing input, it's actively constructing structure from it. The babbling evidence pushes this further. Deaf infants exposed to sign language 'babble' with their hands, on the same timeline hearing infants babble vocally. That tells us babbling isn't really about practicing sound. It's a built-in stage of language readiness that will express itself in whatever modality, spoken or signed, a child is exposed to.
Key terms
- Cooing
- Early vowel-like sounds, such as 'ooh', produced by infants starting around 2 months.
- Babbling
- Repetitive consonant-vowel sounds, like 'bababa', that emerge around 4 to 6 months using sounds from all languages.
- Telegraphic speech
- Short phrases of about two words that omit minor words but preserve core meaning, like 'want cookie'.
- Overgeneralization
- Applying a learned grammatical rule too broadly, producing errors like 'goed' on irregular verbs.
- Holophrase
- A single word used by a young child to express a complete idea or request, such as saying 'up' to mean 'pick me up'.
Watch it explained
- How it worksWalk me through cooing, babbling, one-word speech, and telegraphic speech on a timeline.
- How it worksHow does overgeneralization show that a child learned a rule and not a list?
- Common mistakeWhy isn't a child saying goed evidence that their language is getting worse?
- Going furtherWhat happens to babbling in a deaf infant exposed to sign language?
Check yourself
End of topic.