How do children acquire language, and what explains the universal sequence of language milestones?
Topic 3.5 Communication and Language Development: describe the stages and milestones of language acquisition and explain the major theories of language development, including the role of a critical period.
A focused answer to AP Psychology Topic 3.5, covering the universal sequence of language milestones (cooing, babbling, one-word and two-word telegraphic speech), the building blocks of language (phonemes, morphemes, grammar), the critical period for language, and the nativist, learning, and interactionist theories of language acquisition.
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What this topic is asking
Topic 3.5 covers how children acquire language. The College Board wants the universal sequence of milestones (cooing, babbling, one-word, two-word telegraphic speech), the building blocks of language (phonemes, morphemes, grammar), the idea of a critical period, and the competing theories of language acquisition.
The building blocks of language
The universal sequence of milestones
Children everywhere pass through the same stages in the same order, a key piece of evidence in the unit:
- Cooing (~2 months): vowel-like sounds.
- Babbling (~4 to 6 months): a wide range of speech-like sounds, including sounds not in the child's native language. Babbling narrows over time toward the native tongue.
- One-word / holophrastic stage (~1 year): single words used to convey whole ideas ("milk").
- Two-word / telegraphic stage (~2 years): condensed two-word phrases ("want cookie") that omit articles and endings, like a telegram.
The critical period
A critical period is an early window during which language is acquired most readily. Children who are not exposed to language during this window (as in rare cases of extreme deprivation) struggle to fully acquire a first language later. This supports a strong biological component to language.
Theories of language acquisition
- Nativist (Chomsky): humans are born with an innate language acquisition device, a biological readiness that lets children extract grammar from limited input. Evidence: the universal sequence and the speed of acquisition.
- Learning (Skinner): language is acquired through reinforcement, imitation, and association, like any other behavior.
- Interactionist: language emerges from the interaction of an inborn capacity with social experience and exposure.
This topic is a clean illustration of the unit's nature-and-nurture theme. The universal milestone sequence and the critical period point to a strong biological foundation (Chomsky's nativism), while the fact that a child learns the specific language of their environment, with its particular phonemes and vocabulary, shows the indispensable role of experience (Skinner's learning view). The interactionist position holds both together, and that is usually the safest answer in an FRQ. When a scenario gives you a toddler's speech, the move is to name the exact stage or building block (phoneme, babbling, telegraphic speech, overgeneralization) rather than describing it loosely.
Try this
Q1. Describe telegraphic speech and give the approximate age it appears. [2 points]
- Cue. Two-word phrases of mostly nouns and verbs with grammatical words omitted, appearing around age 2.
Q2. State Chomsky's nativist explanation of language acquisition. [1 point]
- Cue. Humans are born with an innate language acquisition device that lets children extract grammar from limited input.
Exam-style practice questions
Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AP 2023 (style)1 marksMultiple choice. A toddler says 'want cookie' and 'mommy go,' producing two-word phrases that omit articles and verb endings. This pattern is best described as which of the following? (A) Babbling (B) Cooing (C) Telegraphic speech (D) Overgeneralization (E) A phonemeShow worked answer →
The answer is (C) Telegraphic speech.
Telegraphic speech is the early two-word stage in which children produce condensed phrases containing mostly nouns and verbs while omitting articles, prepositions, and word endings, like a telegram.
(A) babbling is the earlier production of speech-like sounds before real words. (B) cooing is the earliest vowel-like sounds in infancy. (D) overgeneralization is misapplying a grammar rule (such as 'goed'). (E) a phoneme is a single unit of sound, not a phrase.
AP 2022 (style)4 marksConcept-application free-response question. A linguist studies a young child's speech. Explain how EACH of the following applies: a phoneme, babbling, telegraphic speech, and the critical period for language.Show worked answer →
A 4-point concept-application FRQ; one point per term.
Phoneme (1): the smallest distinctive unit of sound in a language; the child must learn to produce and distinguish the phonemes of their language.
Babbling (1): the stage in which the infant produces a wide range of speech-like sounds, including sounds not in the native language, before producing words.
Telegraphic speech (1): the early two-word stage of mostly nouns and verbs with grammatical words omitted.
Critical period (1): the early window during which language is most readily acquired; learning a first language becomes much harder if it is missed.
Markers reward each term being correctly defined AND tied to the child's language development.
Related dot points
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Sources & how we know this
- AP Psychology Course and Exam Description — College Board (2024)