Speech, Language, and Communication Development
Milestones a candidate must know
Understand the sequence: cooing (2–3 months), babbling (6–9 months), first words (around 12 months), two-word combinations (18–24 months), and rapid vocabulary growth with grammar emerging between 2 and 3 years. By 3 years, most children are intelligible to unfamiliar listeners; by 4, they use complex sentences and most speech sounds are acquired, though /r/, /l/, /s/, /θ/ may emerge later. Receptive language typically precedes expressive language. Pragmatics (turn-taking, joint attention) develops alongside form and content.
Theoretical frames
Know behaviorist (Skinner), nativist (Chomsky, LAD), and interactionist/social (Vygotsky, Bruner) views. These appear as conceptual questions rather than clinical ones.
Traps in questions
A common trap is treating a single missed milestone as a disorder; questions reward knowing the range of normal variation. Another trap is confusing speech (articulation, voice, fluency) with language (phonology, morphology, syntax, semantics, pragmatics). Do not label a bilingual child's code-switching or silent period as a disorder. Watch for questions that present a child with limited words but good comprehension-this is expressive delay, not global delay.
Rule of thumb
Use the "12 by 12" heuristic cautiously: about one word by 12 months, roughly 50 words and two-word combinations by 24 months. Significant deviation warrants screening, not immediate diagnosis.
Worked example: A 30-month-old with 15 words and no two-word combinations shows expressive delay requiring evaluation; a 30-month-old using 200 words and short sentences is within normal range.