First Language Acquisition: Key Concepts (Concise Notes)

Naturalistic approach: observe children’s spontaneous utterances over time; longitudinal design tracks development in individuals. Pitfall: not ideal for testing specific hypotheses.
Experimentation: designed tasks to elicit targeted phenomena (comprehension, production, imitation). Pitfall: performance can be affected by non-linguistic factors (inattention, shyness).

Babbling: begins around $6$ months; frequency increases toward $12$ months; pattern becomes more language-dependent around $18$ months. Vowels acquired before consonants; stops acquired before other consonants.
Typical order of place of articulation development: labials (p, b, f, v) → alveolar (t, d, s, z) → velar (k, g, ŋ) → interdental (θ, ð).
Perception vs production: children often perceive phonemic contrasts (e.g., $p/b$ , $t/d$ ) before producing them reliably.

IPA categories: Consonants (place, manner) and Vowels (height, backness, rounding).
Major groups: bilabial, labiodental, dental, alveolar, postalveolar, retroflex, palatal, velar, uvular, pharyngeal, glottal; manners include plosive, nasal, trill, tap/flap, fricative, lateral fricative, approximant; vowels span front-central-back with height distinctions (close, close-mid, open-mid, open).
Notation conventions: symbols on the right typically voiced; left denote voiceless; shading indicates articulations considered impossible.

Syllable deletion: stressed syllables more likely retained than unstressed ones (e.g., in multisyllabic words).
Syllable simplification: deletion/reduction to simplify syllable structure.
Clustering reduction: simplification of consonant clusters (e.g., stop–stop reductions).
Final-consonant deletion: e.g., bus → bu, dog → do.
Substitution processes:
- Stopping: fricative replaced by a stop (e.g., s → t).
- Fronting: place of articulation moved forward (e.g., k → t).
- Gliding: liquid replaced by a glide (e.g., r/l → w/j).
- Denasalization: nasal replaced by a non-nasal (e.g., n → d).
- Assimilation: features of a sound change under influence of neighboring sounds.

Milestones:
- At $18$ months: roughly $50$ words.
- By age $6$ years: around $14{,}000$ words.
- By adolescence: around $60{,}000$ words.
Rate: substantial daily growth in early years; word acquisition accumulates to thousands by school-age.

Whole object assumption: a new word refers to the whole object.
Type (kind) assumption: refers to a kind, not just a single object.
Basic level assumption: refers to objects alike in basic ways (appearance/behavior).
Contextual clues: use surrounding information and determiners to infer category/meaning (e.g., determiners like $a,\; the$ ).
Meaning errors:
- Overextensions: the child’s word is more general than adult meaning (e.g., dog → all four-legged animals).
- Underextensions: overly restrictive use of a word.

Typical phonetic processes to identify in child speech include: stopping, fronting, gliding, denasalization, and assimilation.
Transcriptions from two-year-old speech illustrate various substitutions and simplifications; identify the processes accordingly.