6-month-olds are sensitive to English morphology

Area of Science:

• Developmental Psychology
• Linguistics
• Cognitive Science

Background:

• Languages use morphological suffixes (e.g., -s, -ed) to convey grammatical information like number and tense.
• These suffixes are fundamental to syntax and meaning in language acquisition.
• Prior research indicated infants recognize suffixes on known words earlier than on novel words.

Purpose of the Study:

• To re-evaluate English-learning infants' knowledge of morphological suffixes within their first year of life.
• To determine if infants can acquire morphology independently of word meaning.
• To investigate the developmental timeline of morphology acquisition relative to phonology and meaning.

Main Methods:

• Infants aged 6 and 8 months were tested on their ability to segment and relate nonce words with various suffixes (-s, -ing, -ed, -sh).
• Familiarity/preference procedures were used to assess recognition and relatedness of suffixed nonce words to their stems.
• The study compared infants' responses to real suffixes versus a pseudo-morpheme.

Main Results:

• Six-month-olds successfully segmented nonce words with suffixes -s, -ing, -ed, and -sh.
• Six-month-olds related nonce words with -s to stems but not those with -ing, -ed, or -sh.
• By eight months, infants also related nonce words with -ing to stems, demonstrating developing morphological knowledge.

Conclusions:

• Infants demonstrate knowledge of morphological relatedness from early stages of language acquisition.
• Morphological acquisition can occur even without explicit access to word meaning.
• The acquisition of morphology may develop concurrently with phonology and meaning, not solely after meaning is established.