Development of CDIs for rural Africa K. Alcock K. Rimba A. Abubakar P. Holding

Assessing vocabulary and grammatical development “Clinical” testing –e.g. Picture vocabulary tests, TROG, elicited speech –Carter et al. Laboratory testing (HA!) Spontaneous speech samples Checklists –Fenson et al. –Bornstein et al. crosslinguistic

Bornstein et. al 2004 Data from 7 languages Checklist similar to MacArthur/Bates but shorter All have higher noun proportion. in 20mo vocabulary –Even Korean – unlike previous data –Suggest child constraints lead to this –But modified by language features

Two East African languages Kiswahili and Kigiriama –Both spoken in coastal Kenya –Town and. village families

Overall study Impact of HIV exposure on child development Age 6 months to 3 years Language, motor and cognitive development 200 families so far

Relevant sentence features Very variable word order The child likes potatoes Mtoto anapenda viazi – basic word order SVO Anapenda viazi mtoto – common, VOS Mtoto viazi anapenda – less common but possible, SOV Sentences can miss out subject He likes potatoes Anapenda viazi Rather like Italian in that respect Sentences can miss out subject He likes (them) Anapenda/Anavipenda

Data collection Adaptation of MacArthur CDI 175 families of children aged 8-15 mo Interview technique - not literate

Construction 1 Macarthur-Bates CDI - younger (words & gestures) Elimination of inappropriate words (snow, penguin) Translation in parallel to both languages

Construction 2 Adding words: –RAs experienced w. children –Mothers on staff & in community –Speech samples –Situational vocabulary (goat, maize porridge) –Function words Back translation & checking

Construction 3 MacArthur-Bates CDI Older (Words and Sentences) Same method with vocabulary Grammatical development: –Spontaneous samples –Examination of errors actually made –Enumeration of parts of speech children need to learn –Not possible to produce an order of learning in the time –But we will be able to tell what is learnt between months

Validation Internal validity External validity –Vocabulary and gestures – 9-15 months –Vocabulary and grammar – months

Production 8-15 mo

Comprehension mo

Production mo

Word combining mo

Reliability and validity Internal reliability –Alphas over.9 for most sections –Alphas much over.9 for half of test Correlation with age –Total vocabulary (younger).505 –Gestures.679 –Total vocabulary (older).620 –Grammatical affixes.469 Effect of HIV –When covary age, vocabulary approximately half that of community children

Validity testing 9-15 months Challenge items –Production, comprehension and gesture –Low, medium, and high frequency Mother list of words

Challenge items No child produced any words in production –Some incomprehensible sounds Comprehension and gesture more useful –Significant correlations: Gesture without prompt and gesture on CDI Gesture without prompt and comprehension on CDI Specific items tested in comprehension challenge did not correlate with challenge comprehension items

Mother lists of words –Neither prompted nor spontaneous lists correlate with: Age Gesture total Language total Challenge task –Asked for words for actions/toys/things child likes tends to give names of actions child can do etc.

Conclusions for validity Test hugely internally valid Mothers better at observing gesture than language? 10 challenge words very poor test? Mother spontaneous list paradigm poorly understood –CDI paradigm involves clearer explanation –Reminder “can he say the word or does he just understand the word”

Summary Reliability of test Validity Further work –Spontaneous speech during cognitive testing session But no speech produced –Spontaneous speech at home –Written versus interview method for literate local mothers