Language: Individual differences

1. Language: Individual differences Daniel Messinger, Ph.D.

2. Language overview review • What is the normative course of infant language development?  • How do infant cries develop (directed and undirected)? • What are the stages of development of non-cry vocalizations? • What are some early milestones of verbal development (verbal development involves words)?

3. Perspective • Last time • Features of language that all infants develop • Focus on production: speech • This time • How infants differ in learning language • Differences in learning to hear a first language • Differences in learning to talk a first language • Autism and deafness

4. Today’s questions • How does the ability to distinguish between non-native speech sounds change in the first year? • What does this mean about development? • Can distinctions between non-native sounds be taught? • How is language experience associated with later child language competence and IQ? • How is socioeconomic status associated with differences in language experience? • What does cochlear implantation teach us about language development?

5. Consider the spoken tokens of “doll.” • To a Hindi speaker, the difference between the “d” sounds in “this doll” versus “your doll”—a phonetic contrast between a dental [d̪al] versus a retroflex [ɖal], respectively—would signal two possible word forms (either lentils or branch). • In English, both of those “d” sounds signal just one possible word form—phonetically labeled as an alveolar [dal].

6. Different languages provide different phonetic experiences

7. What’s going on? • English-learning infants hear Hindi contrast better than English-speaking adults • Almost as well as adult Hindi-speakers

8. Distinguishing between non-native speech sounds in 1st year • At birth, infants are capable of discriminating all phonetically relevant differences in the world’s languages • They perceptually partition the acoustic space underlying phonetic distinctions in a universal way. • By 6 months of age, infants raised in different linguistic environments show an effect of language experience. • Their representations are becoming language specific

9. How does this develop? • Infants lose this ability in the first year of life, especially toward one year of age

10. What this mean for development • Very young infants can discriminate a wide range of phonetic contrasts in a variety of languages • Between 1 & 12 months, infants • increase knowledge of which syllables follow which in their native language • but lose ability to make contrasts that do not occur in their native language • /r/ vs. /l/ . /b/ vs. /v/ . Te’ vs. te, tu’ vs. too • Development involves relatively permanent change, but not always improvement in all things.

11. Parallels in speech production • Infant babbling shows little influence of native language. • Once the infant forms his/her 1st words than the sounds produced conform more closely to those of the native language • This corresponds to the stage at which infants begin to show language-specific sensitivity (10-12 months).

12. Possible roles of experience Induction – prior experience with a language is necessary because perceptual capability depends entirely on environmental input Attunement – experience makes possible the full development of a capability. Facilitation – experience effects only the rate of development of a capability. Maintenance/loss – the ease in which a capability is fully developed before the onset of experience, but experience is necessary to maintain the capability. Maturation – development of a capability independent of experience

13. Perceptual Magnet Effect • Instances of sounds that belong to a category are drawn toward the Prototype. • Physical (acoustic) vs. perceptual maps • the latter differ for speakers of different languages

14. Can distinctions between non-native sounds be taught? • Cheour has experimentally produced this “development” • In sleeping neonates • Using changes in neural responses to sounds as an outcome variable • http://www.med.cornell.edu/news/press/2002/feb_22_newborn.html

15. How sleeping babies learn • The babies had electrodes placed on their scalps, and speakers near their heads gently played a randomized sequence of two similar Finnish vowel sounds as they slept: a "standard" sound, /y/, and a "deviant" sound, /i/.

16. Mismatch Negativity (MMN) • “ when the brain hears the standard sound, there is a certain response in the brain, and when it hears the deviant sound, there is another response. • Subtracting the responses to the deviant from the responses to the standard produces the MMN.”

17. Training • No initial MMN for any group (N=15). • Over the following night, for between two-and-a-half and five hours, the experimental group had a "training" session of exposure to the two sounds. • /y/ vs. /i/. • One control group did not have this exposure, and the other control group heard two different sounds, /a/ and /e/.

18. Results • The experimental group showed significant mismatch negativity to the deviant sound. • The babies had learned to distinguish between these two Finnish vowels. • Persisted for at least 24 hours. • The two control groups showed no MMN to the deviant sound.

20. Conclusion • "We have shown that newborns can assimilate auditory information while they are sleeping, suggesting that this route to learning may be more efficient in neonates than it is generally thought to be in adults." • Cheour • Is this learning?

22. Reviewing the power of language • More maternal vocalizing at 1 month • Associated with vocalizations at 8 & 24 months and with socioeconomic status • Also predicts greater adolescent intelligence • R2 = .22 for gazing and maternal vocalizations

23. Overview • Socioeconomic differences in how folks talk to their kids • What impact might it have? • How is language experience associated with later child language competence and IQ?

24. Socioeconomic status differences in language experience are associated with later child language competence and IQ • Meaningful differences in the everyday experiences of young American children. Hart & Risley (1995). Baltimore, MD: Brookes Publishing Co • Some text from summaries by Susan Brunner, Dahra Jackson, and Amy Vaughan

25. Participants • Longitudinal project from 9-10 months infant age up until 2-2 ½ years later • 42 families observed for one hour every month, at home, in natural settings • recruited from birth announcements, friends and families at University pre-school, WIC meetings, and state records • all but 8 families were intact, all but one had a male figure involved • 13 upper SES, 10 middle SES, 13 lower SES, and 6 families on welfare; all “well-functioning”

26. Data collection • Observers transcribed and audio-recorded all verbalizations and interactions that would have an effect on another person; never interacted with child, but responded to parents • Observers assigned to families for entire study, when possible, and similar to family in terms of background • no drop-outs after first year, reliability on coding and observations was adequate • words coded as part of speech, episodes coded by type, and speaker coded; dictionaries compiled for each speaker (all on computer)

27. Commonality • Despite how strikingly different the families were in how much talking and interaction typically went on in the home, just socializing during everyday activities was sufficient for all children (regardless of SES) to learn to talk by age 3.

28. 42 Families and the Differences Among Them • differences observed in family language style: parents’ language seemed to reflect the number and variety of behaviors they had for dealing w/ their children • some families talked more than others, and this was variable within families from month-to-month, but stable over the 3 years • birth order and family size affected the amount of talk each child received, but did not affect the total amt. of talk

29. SES seemed to make the biggest contribution to both amount of talk and time spent in interactions, with hi SES at an average of 482 wds/hr and 48 mins/hr, and welfare families at 197 wds/hr and 17 mins/hr

30. Language and SES (class) • Children from all backgrounds have the same kinds of everyday language experiences. • But more economically advantaged children differ in the amount of these experiences; it is the frequency that matters. • More opportunities for learning language occur when children engage in many and varied interactions with other people; families tend to be consistent in the opportunities they provide for their children.

31. Talk that teaches talk • THEY JUST TALKED • parents talked beyond what was needed to provide care • THEY LISTENED • To add information and prompt elaboration • THEY TRIED TO BE NICE • When enforcing a rule • THEY GAVE CHILDREN CHOICES • THEY TOLD CHILRESN ABOUT THINGS • Things worth noticing or remembering (Halloween)

32. Quantity of language: Nouns, adjectives, and adverbs to child

33. Being positive • Repetitions, extensions, expansions, confirmations, praise, approval over all feedback (including imperatives, criticisms, etc).

34. Relating things and events • Nouns, modifiers, and past-tense verbs divided by number of utterances per hour

35. “Can you. . . ?” • Proportion of yes/no questions over yes/no questions and imperatives

36. Responsiveness • ‘Ok’ ‘I see’ • % of responses not preceded by an initiation

37. How language experience is associated with later child IQ • “Parenting” = Language diversity + feedback tone + symbolic emphasis + guidance style + responsiveness • Predicts between and within SES groups

38. Language experience makes the difference

39. Implications for intervention • ‘To intervene with vocabulary growth rate … increase the experiences available to the children • Limited success … ultimately the growth rates increased only temporarily. • Could easily increase the size of the children’s vocabularies, could not accelerate the developmental trajectory.’ • “Removing barriers and offering opportunities and incentives is not enough to overcome the past, the transmission across generations of a culture of poverty.”

40. Is environmental influence global or specific? • We know that there are differences in language development across SES • Mothers are primary source of language-experience • Does maternal speech mediate the relation between SES and child vocabulary development? The Specificity of Environmental Influence: Socioeconomic Status Affects Early Vocabulary Development Via Maternal SpeechErika Hoff

41. Maternal speech fully mediates relationship between SES and child vocabulary! • SES -> 5% of variance in child vocabulary • SES significantly associated with maternal speech • MLU -> 22% of variance in child vocabulary • When removed, only 1% of variance explained by SES • So…there are 2 processes going on • 1. SES affects maternal speech • Childrearing beliefs • Time availability • 2.Maternal speech affects language growth • Provides data for child’s word-learning mechanisms • Longer utterance -> more variance in word types (richer vocabulary) • Longer utterance -> more info about meaning • Longer utterance -> richer syntax

42. Support environmental specificity model • Vocabulary development depends on specific properties of language experience • Implies that enriching language experience can increase vocabulary development for low-SES kids

43. Niparko et al., 2010 Romero

44. Earlier implantation, earlier language gains Romero

45. Receptive Language Romero

46. Expressive Language Romero

47. Other findings • Higher parent-child interactions and higher socioeconomic status were associated with greater rates of language learning. • Bilateral implantation was not associated with an increase in language acquisition. • Gender was not associated with an increase in language acquisition. Romero