Language developmentLecture Notes: 9/18/14Stages of Babbling● Reflexive vocalizations (0-2 months)○ Crying, coughing, sneezing○ Determined by vocal physiology in infants● Cooing and laughter (2-4 months)○ Sounds of content○ Usually made in the back of the mouth● Vocal play (4-6 months)○ Experimental play with the sounds○ Sounds become more consonant-like and vowel-like○ Repertoire is limited: velar consonants (g,k) early on, labials and alveolars later on (m, n, p, b, and d) ○ Loud vs. soft, high vs. low, sustained vowels○ Raspberries (bilabial trills) Canonical Babbling (6+ months)● Sequence of vowels and consonants = true syllables● Syllables have adult-like timing, and sound like attempts at words● Sequences of same syllables (mamama) = reduplicated babbling; lasts until 12 months○ Not always communicative; first stage of speech productions that distinguishes hearing and deaf infants● Sequences of different syllables (magibu) = variegated babbling; predominates after 12 months Jargon Stage (10 months+)● Conversational babble or modulated babble● Strings of syllables spoken with language-appropriate stress and intonation● Often overlaps with early meaningful speech● Shows grasp of suprasegmentals and of social nature of conversation ● In normally developing children, disappears by 2 years of ageRole of Feedback● People around the infant = external feedback○ Speech around the child reinforces appearance of certain sounds (frequent sounds appear earlier● Infant herself = internal feedback○ Hearing oneself speak and comparing it to speech of others○ Reinforces learning○ Deaf children will learn sign language from parents (can compare their signs to signs of their parents), but nor oral language (cannot compare their vocalizations to speech production of their parents)In sum● Ability to discriminate all sound categories disappears around 6-12 months of age (onsetof language-specific speech perception)● Babbling progresses through stages of development and evolves into meaningful speechPhonotactics● Each language has a set of its own constraints● In English: ○ Words cannot start with a velar nasal /n/■ I.e. sing is Ok, but ngis is not■ Words cannot start with /lp/ and /rt/ clusters (can say “plug” but cannot say “lpug”) ● Can get frequency counts for how often two sounds occur next to each other in spontaneous speech○ Higher frequency = easier pronounceability = easier acquisition What are the Phonological/Articulation Errors due to?● Structural/anatomical abnormalities● Normal developmental patterns● Delay/disorder in phonological developmentStructural/Anatomical Abnormalities● Severe (like cleft palate) Phonological Errors Children Make in the Course of Normal Development● Occur due to immaturity of phonological knowledge and/or inherent difficulty with some sounds vs. others● Stepping stones on the path to adult phonology● Not necessarily due to difficulty in perceiving the sound● Usually follow a pattern● Systematically differ from phonology of adults, and follow a specific processThe Errors Children Make● Weak syllable deletion○ Omission of a weak (unstressed) syllable that comes before or after a stressed syllable○ Examples: “telephone” pronounced as “tefone”; “above” pronounced as “bov”; “tomato pronounced as “may-toe”○ Often due not to difficulty with particular sound, but to difficulty with suprasegmentals- stress patterns (i.e., unstressed, weak syllables are more difficult to hear)● Final Consonant Deletion○ A child reduces a syllable by omitting the final consonant of that syllable○ Usually, word-finally○ Example: pot as paw● Cluster Reduction○ When a consonant is deleted from a consonant cluster (two or three consonants strung together)○ Even when two sounds can be produced individually, difficulty with pronunciation within a cluster■ Example: snow pronounced as no○ Sometimes, replace the cluster with a single sound, to match the whole cluster inquality■ Example: spot is pronounced as fot (f is an attempt to match the fricative quality of s and keep the place of articulation of p)● Gliding○ Replacing the consonants /l/ and /r/ with the approximants /w/ and /j/○ Examples:■ Rabbit pronounced as wabbit■ Hello pronounced as heyo■ Look pronounced as wook■ Carrot pronounced as cawet● Assimilation○ A sound change where one sound is made to sound closer to another sound nextto it○ E.g. assimilation of voicing = when an unvoiced consonant preceding the vowel that is voiced■ Examples: “pig as “big; “cup” as “gup”○ E.g. consonant harmony (assimilation of place of articulation)■ Examples: “cupboard” is pronounced as “pubbed”; “dog as