Questions: Acquisition of Formal Grammar and Parameters

Question 1

A child acquiring Spanish begins producing grammatically correct null-subject sentences ('Habla bien') after minimal exposure, without explicit instruction. Shortly after, the same child spontaneously allows verb-subject inversion in declaratives and omits expletive subjects — properties they have never heard directly exemplified together. What does formal acquisition theory say happened?

• A. The child inferred each grammatical rule separately through statistical pattern recognition over many examples
• B. Setting the [+pro-drop] parameter based on positive evidence triggered cascading effects — a cluster of correlated properties predicted by a single parameter value
• C. The child's caretaker modeled all three properties simultaneously, allowing direct imitation
• D. Universal Grammar contains specific rules for Spanish that activated when the child heard Spanish input

Answer: (B)

This is the cascading effects phenomenon. The [+pro-drop] parameter doesn't just license null subjects — it is part of a cluster of correlated grammatical properties that co-occur across languages. Languages with null subjects also tend to allow freer verb-subject inversion in declaratives, permit expletive-less existentials, and show strong agreement morphology. A child who sets the parameter based on simple positive evidence (hearing null-subject sentences) has acquired the entire correlated cluster in one step — including properties never directly observed. This is evidence for the parameter model: the child isn't learning these facts one by one, they're following from a single underlying setting.

Question 2

What is the 'poverty of the stimulus' problem, and why is it considered a key argument for Universal Grammar?

• A. Children hear too little language to develop large vocabularies, suggesting vocabulary is partly innate
• B. Children acquire abstract grammatical constraints they have never been directly taught and that go far beyond what the input logically licenses — implying an innate structure guiding acquisition
• C. Children's input is impoverished because adults simplify speech (motherese), which slows acquisition
• D. Children cannot hear all phonemes in the world's languages, so an innate phonological inventory must restrict what they can learn

Answer: (B)

Poverty of the stimulus is specifically about syntax: children reliably acquire grammatical knowledge — complex constraints on movement, binding, island sensitivity — that they have never been directly taught and that the input, no matter how carefully examined, cannot logically license through induction alone. Adults couldn't state these constraints as rules. The argument is that this gap between input and acquired knowledge is only explicable if children bring an innate grammatical structure to the task: Universal Grammar with parameters waiting to be set by positive evidence.

Question 3

Syntactic acquisition is slow and error-prone because children is expected to gradually induce grammatical rules from the statistical patterns in the language they hear.

• T. True
• F. False

Answer: False

This describes vocabulary and pragmatic acquisition, not syntactic acquisition. Syntactic parameters are discrete — either set or not set — and they are set by positive evidence without requiring extensive accumulation of examples. Once a parameter is set, the corresponding grammatical properties emerge quickly and relatively error-free. This contrasts sharply with vocabulary (each word requires repeated exposure) and pragmatics (contextual inference and cultural knowledge accumulate slowly). The formal acquisition account predicts exactly this difference: syntactic acquisition should be fast and clean, and cross-linguistic acquisition data largely support this prediction.

Question 4

In formal acquisition theory, setting a single parameter can account for multiple grammatical properties of a language simultaneously, because different surface phenomena are consequences of the same underlying parameter value.

• T. True
• F. False

Answer: True

This is the cascading effects property and it is central to why the parameter model is explanatorily powerful. Rather than explaining null subjects, verb inversion, and expletive omission as three separate facts requiring three separate learning events, the parameter model explains all of them as consequences of one setting: [+pro-drop]. The model's prediction that these properties should cluster together across languages, and be acquired together by children, has been substantially supported by cross-linguistic acquisition research. Cascading effects are what give the parameter model empirical traction beyond simply positing innate grammar.

Question 5

Why, according to the parameter-setting model, does syntactic acquisition require only positive evidence — while vocabulary and pragmatic acquisition require extensive accumulated experience?

Model answer: Syntactic parameters are binary settings in a pre-specified universal system: the child does not learn what the options are, only which option the target language has chosen. Positive evidence — a grammatical sentence of the right type — is sufficient to trigger the correct setting. The child does not need to hear ungrammatical sentences, be corrected, or accumulate many examples of the same pattern. By contrast, each vocabulary item must be individually mapped from form to meaning through repeated exposure, and pragmatic knowledge requires building up contextual inference patterns from social experience. Parameters have a discrete, constrained search space; vocabulary and pragmatics have open-ended, continuous search spaces that require statistical accumulation.

This asymmetry explains a striking fact about child language: syntactic knowledge arrives quickly and with few errors, while vocabulary grows slowly and pragmatic competence takes years to approach adult levels. The formal model predicts this precisely because syntax is parameter-driven (discrete, fast, positive-evidence-only) while other domains are not.