Language Development: Phoneme Discrimination, Milestones, and Theories

Language Development

Distinguishing Speech Sounds

Understanding how infants perceive and distinguish speech sounds is a foundational topic in developmental psychology. Research by Janet Werker in the 1980s provided key insights into infants' phoneme discrimination abilities.

• Phoneme Discrimination: Phonemes are the smallest units of sound in a language that can distinguish meaning (e.g., 'r' vs. 'l').

• Infants are born with the ability to distinguish between all phonemes, even those not present in their native language.

• By around 12 months, infants' ability to distinguish non-native phonemes declines, and they become better at distinguishing phonemes in their native language.

• The head-turn method is used to test infants' ability to discriminate sounds by measuring their head movement in response to changes in sound.

• Research shows a sensitive period for phoneme discrimination, after which the ability to distinguish non-native sounds decreases.

Example: Japanese infants initially can distinguish between English 'r' and 'l' sounds, but this ability diminishes by 12 months if not exposed to English.

Language Milestones

Language development follows a predictable sequence of milestones, with comprehension generally preceding production. These milestones reflect both biological maturation and environmental influences.

• Cooing (2-4 months): Production of vowel-like sounds (e.g., "oo", "aa").

• Babbling (6-10 months): Repetitive consonant-vowel combinations (e.g., "ba-ba", "da-da").

• First Words (10-14 months): Use of single words to convey meaning.

• Telegraphic Speech (18-24 months): Two-word combinations that omit non-essential words (e.g., "more juice").

• Overregularization (2-4 years): Application of regular grammatical rules to irregular cases (e.g., "goed" instead of "went").

• Adult-like Grammar (5+ years): Mastery of complex sentence structures and vocabulary.

Average Age	Productive Language Milestones
2-4 months	Cooing (vowel sounds: "aa", "oo")
6-10 months	Babbling (consonant-vowel combinations: "ba-ba", "da-da")
10-14 months	First words (single words with meaning)
18-24 months	Telegraphic speech (short, two-word utterances)
2-4 years	Overregularization (applying regular rules to irregular words)
5+ years	Adult-like grammar and vocabulary

Example: A child saying "goed" instead of "went" demonstrates overregularization, a normal part of language development.

Theories of Language Development

Several major theories explain how children acquire language, each emphasizing different mechanisms and influences.

Theory	Proponent	Summary	Critique
Behaviorist Theory	B.F. Skinner	Language is learned through operant conditioning and reinforcement. Children imitate sounds and words, and adults reinforce correct usage.	Cannot account for novel utterances or rapid language learning. Underestimates innate biological factors.
Nativist Theory	Noam Chomsky	Humans are born with an innate universal grammar. Proposes a sensitive period for language acquisition. Children produce novel sentences not heard before.	Underestimates the role of social interaction and environment. Hard to find direct evidence of universal grammar.
Interactionist Theory	Jerome Bruner	Language development is driven by both biological predispositions and social interaction. Emphasizes the importance of child-directed speech and scaffolding.	Clearly acknowledges both nature and nurture, but some aspects of language learning remain unexplained.

Example: The nativist theory explains why children can generate sentences they have never heard before, while the interactionist theory highlights the importance of parental input and social context.

Key Terms and Concepts

• Phoneme: The smallest unit of sound in a language.

• Overregularization: The application of regular grammatical rules to words that are exceptions (e.g., "mouses" instead of "mice").

• Telegraphic Speech: Early speech stage where children use short, simple combinations of words.

• Head-turn Method: Experimental technique to assess infants' ability to discriminate sounds.

• Sensitive Period: A developmental window during which language acquisition occurs most easily.

Additional info: The materials also include multiple-choice questions to reinforce understanding of these concepts, such as identifying examples of overregularization and recognizing the developmental stage of babbling.