Language Development

Every board exam for psychometricians includes at least one item on language milestones or theory, because language acquisition is the clearest window psychology has into how the mind develops. A wrong answer here usually comes from mixing up a milestone's age, or from crediting the wrong theorist for the wrong mechanism. This lesson walks through the building blocks of language, the sequence every child follows, and the three competing accounts of how it all happens.

The five components of language

Linguists and developmental psychologists break language into five subsystems, and the board expects you to tell them apart on sight.

• Phonology is the sound system of a language: which sounds (phonemes) exist and how they may combine. A child who says "wabbit" for "rabbit" has a phonology still under construction.
• Morphology governs the smallest units of meaning (morphemes) and how they combine into words, including plural or tense markers like "-s" and "-ed."
• Semantics is the meaning system: the vocabulary a child holds and the concepts each word maps onto. Errors show up as overextension (calling all four-legged animals "doggie") or underextension (using "dog" only for the family pet).
• Syntax is grammar in the narrow sense: the rules for ordering words into acceptable phrases. A child who says "throw ball me" instead of "throw the ball to me" has a syntax still developing.
• Pragmatics is the social use of language: taking turns, adjusting speech to the listener, requesting, greeting, protesting. A child with strong syntax but poor pragmatics (interrupting, ignoring listener cues) has a distinctly different profile from one whose grammar itself is delayed, a contrast the board tests when distinguishing social communication difficulties from a purely structural language disorder.

Keep these five apart: a test item about "the child cannot order words correctly" is testing syntax, not semantics, even though both feel "grammar-adjacent" in casual speech.

The milestone sequence

Language unfolds in a strikingly consistent order across children and cultures, and the exam rewards memorizing the sequence with rough ages attached.

• Cooing (about 2 to 4 months). Vowel-like, musical sounds ("ooh," "aah"). This is prelinguistic and appears even in deaf infants, showing a biological readiness for vocalization.
• Babbling (about 6 months). Consonant-vowel strings ("ba-ba," "da-da"). Reduplicated babbling (one repeated syllable) gives way to variegated babbling (mixed syllables), and by around 10 months babbling narrows toward the phonemes of the home language.
• The one-word or holophrastic stage (about 12 months). A single word functions as a whole idea. A holophrase like "milk!" can mean "I want milk" or "I spilled milk" depending on context and tone, so pragmatics and gesture do heavy interpretive work here.
• The two-word stage and telegraphic speech (about 18 to 24 months). Utterances combine two or more words, dropping articles and prepositions while keeping the high-content nouns and verbs, exactly like a telegram: "want cookie," "mommy go." Telegraphic speech shows syntax (word order) is already systematic even though morphology is not yet complete.
• Overregularization (about 2.5 to 4 years). As children extract grammatical rules, they apply them too broadly to irregular forms: "goed" for "went," "foots" for "feet," "mouses" for "mice." This is one of the field's most important findings, because it is direct evidence children are not simply imitating adult speech (adults never say "goed") but are actively generating rules on their own.
• By about age 5, the core grammar of the native language is largely in place, though vocabulary and pragmatic sophistication (irony, narrative, register-switching) keep developing through the school years.

Stage	Approximate age	What it shows
Cooing	2 to 4 months	Prelinguistic vocalization, biologically driven
Babbling	6 months onward	Sound play, narrowing toward native phonemes
Holophrastic (one-word)	around 12 months	One word carries a whole message
Telegraphic (two-word+)	18 to 24 months	Emerging syntax, missing function words
Overregularization	2.5 to 4 years	Active rule application, not pure imitation

Theories of language acquisition

The board consistently pits three explanations against each other, and the safest way to hold them in memory is by their core mechanism: is language built in, shaped by reinforcement, or scaffolded by social interaction?

Nativism: Chomsky's LAD and universal grammar. Noam Chomsky argued that children could never learn the full complexity of grammar from the limited, often ungrammatical speech they actually hear, a problem he called the poverty of the stimulus. His solution was the Language Acquisition Device (LAD), an innate, biologically built-in structure that lets any child extract the grammar of whatever language surrounds them. He also proposed universal grammar: a shared set of grammatical principles across all human languages, which is why children everywhere pass through the same milestone sequence regardless of which specific language they learn. Overregularization is the nativists' favorite evidence, since it shows rule-generation, not mimicry.

Learning theory: Skinner's operant account. B.F. Skinner, in Verbal Behavior (1957), argued language is learned like any other behavior, through operant conditioning: caregivers selectively reinforce sounds that resemble real words, and through shaping, successive approximations gradually turn babble into speech, while imitation of adult models fills in vocabulary and phrasing. This explains vocabulary growth reasonably well but struggles with overregularization and with novel, grammatical sentences a child has never heard reinforced, precisely the gap Chomsky's famous critique of Skinner exploited.

Social-interactionism. Drawing on Lev Vygotsky and later Jerome Bruner, this view holds that language emerges from the child's drive to communicate within a responsive social environment, not from an isolated grammar module or pure reinforcement. Caregivers support early language through child-directed speech ("motherese": simplified, exaggerated, higher-pitched), joint attention, and structured routines Bruner called the Language Acquisition Support System (LASS), a deliberate answer to Chomsky's LAD. Both biology and environment matter here, with social scaffolding as the mechanism that turns capacity into actual competence.

Theory	Key figure(s)	Core mechanism	Main evidence cited	Main criticism
Nativism	Chomsky	Innate LAD, universal grammar	Overregularization, poverty of the stimulus, cross-linguistic uniformity	Underspecifies role of social input
Learning theory	Skinner	Reinforcement, shaping, imitation	Vocabulary growth tracks caregiver responses	Cannot explain overregularization or novel grammatical sentences
Social-interactionism	Vygotsky, Bruner	Social scaffolding, child-directed speech, joint attention (LASS)	Language emerges fastest with responsive caregiver interaction	Harder to specify exact universal mechanism

Bilingualism

Bilingual development is a recurring board topic given the Philippines' multilingual reality. Children raised with two languages from birth (simultaneous bilingualism) pass through the same milestone sequence as monolingual children, sometimes with brief code-mixing (blending elements of both languages in one utterance), a normal feature of bilingual development, not a sign of confusion or delay. Children who acquire a second language after the first is established (sequential bilingualism), such as after starting school, draw on the first language's grammatical foundation while building the second. Research generally finds early, sustained bilingualism carries advantages in executive function, particularly cognitive flexibility and inhibitory control, since managing two language systems demands constant selective attention.

In the Philippine context, Republic Act No. 10533 (Enhanced Basic Education Act) mandates Mother Tongue-Based Multilingual Education (MTB-MLE) for the early grades, using the learner's first language as the medium of instruction before transitioning to Filipino and English, because a strong first-language foundation supports later literacy and second-language learning. RA 10029 (Philippine Psychology Act of 2009) governs the practice of psychology and psychometrics itself rather than language policy; examinees should know it as the law that created the board they are sitting for, and should not confuse it with education-language statutes like RA 10533.

Board traps and takeaways

• Do not credit Skinner with explaining overregularization: reinforcement theory predicts imitation of correct adult forms, not children inventing "goed" or "foots," which is nativist evidence for rule-based learning.
• Keep telegraphic speech (missing function words, present syntax) distinct from a holophrase (a single word standing for a whole idea); they belong to different stages, roughly one-word versus two-word-plus.
• Do not confuse universal grammar (a shared grammatical blueprint across all languages) with a specific grammar rule of any one language; universal grammar is Chomsky's explanation for why milestones are cross-culturally uniform.
• Remember Bruner's LASS is the social-interactionist answer to Chomsky's LAD: same acronym shape, opposite mechanism (social scaffolding versus innate structure).
• Code-mixing in bilingual children is normal development, not a language disorder or sign of delay; do not flag it as pathological on a case-based item.
• Sort the five components correctly under pressure: sound is phonology, word-building is morphology, meaning is semantics, sentence structure is syntax, and social/contextual use is pragmatics.