1. Language Acquisition Species-specific, species-universal accomplishment Central issue for cognitive science Important distinction between language comprehension (perception) and language production Start with perception of language in infancy, then move on to production

2. Infant Speech Perception The problem: How does the infant make sense of the stream of sounds of human speech? –Newborns prefer listening to the human voice than to other sounds –Infants under 1 month can distinguish mother’s voice from others –Question: How do we ask infants what they like to listen to and what they can distinguish? –Development of a set of experimental paradigms designed to provide us with just this information.

3. Not a trivial problem for adults Mondegreens (misheard song lyrics) –“laid him on the green"  ”Lady Mondegreen.“ –“Excuse me while I kiss this guy” –“I’ll never be your pizza burnin’” –“The ants are my friends” –“No Dukes of Hazzard in the classroom” –“Tiny little faces, you’re a dickhead in love” Both my children made this segmentation error: –“Are we going to my saga’s?” –Speech perception forms the basis for production

4. Categorical Speech Perception Eimas, Siqueland, Jusczyk, & Vigorito (1971) The voicing contrast is perceived categorically by adults—it’s either /b/ or /p/ with no middle ground. What about babies? Tested 1-month olds using the non-nutritive sucking paradigm: –1 month olds prefer familiar than novel –Suck more vigorously in response to the familiar Played synthesized speech to babies who were allowed to suck freely on a nipple electronically rigged to record the rate of sucking

5. Eimas et al. (1971) Exposed babies to either /ba/ or /pa/, then varied the Voice Onset Time (VOT) VOT of about +35 msec is the boundary for adults 1-month-olds perceive this distinction categorically Infants are sensitive to virtually any phonemic contrast. By end of 1 st year, they lose the contrasts that aren’t in their language. % /b/ VOT 0 +10 +20 +30 +40 +50 +60 +70

6. Other animals perceive speech categorically

7. Just the Beginning This early ability helps infants to “bootstrap” their way into language perception and comprehension Prosodic contours at about 6 months Word boundaries at about 8 months Phrase boundary markers at about 12 months

8. Finding the Words Aslin, Saffran, & Newport (1998) Exposed 8-month-olds to a 2-min continuous stream of synthesized speech –e.g., pabikutibudotudaropigolapabikupigolatibudo –Some sequences had higher conditional probability of occurring than others e.g. pabiku vs. golati –Infants preferred to listen to the high probability sequences –8-month-olds can extract statistical regularities from the speech stream –The regular sequences become “candidate words”

9. Language production Cooing at about 3 months –Mostly vowel sounds Babbling at about 6 months –Reduplicated CV syllables –Clear sound preferences—stop and nasal consonants, back and middle vowels –Biologically pre-wired: Deaf babies babble First words at about 12-15 months First word combinations at about 18-24 months