Language Development and the Brain:
A Phonological Perspective
Usha Goswami
Centre for Neuroscience in Education
University of Cambridge
How does the Brain encode Speech?
-Auditory signal
-Visual dynamics
-Encoding via
oscillations?
The Brain and the Speech Signal
Phonetics – ba / da
NINE
SEVEN
TWO
THREE TWO
Syllable structure
Rhythm
Prosody
Behavioural Science
Babies use speech rhythm as an early segmentation cue
Can also distinguish e.g. ba / pa, syllable stress
What is happening in the Brain?
Envelope and Fine Structure
Smith, Oxenham & Delgutte, 2002: Auditory Chimera
Method for contrasting envelope (slowly varying)
and fine structure (rapidly varying) components
of speech (or other sounds) experimentally
CHIMERA =
Envelope cues from one sentence
Fine structure cues from another sentence
Which sentence will listeners hear?
Auditory Chimera Sentences
Perception mainly from fine structure
Not much from envelope
Perception mainly from envelope
Not much from fine structure
Envelope information most
important for speech intelligibility
Early language acquisition:
critical role for envelope?
Envelope information most
important for speech intelligibility
Emphasises importance of speech
rhythm and syllable structure
Envelope: Importance of Rise Times
Combination of Cues Important
“SEVEN”
Spectro-Temporal Profile (STeP)
Spectro-temporal profile (STeP)
Spectrogram+Waveform
Spectrogram + Waveform
Greenberg et al. (2003)
“Seven”
Amplitude Envelope and Stressed
Syllables
Full-spectrum
[s] [eh] [vx] [en]
perspective
accented
syllable
juncture
unaccented
syllable
Rise times
[eh]
[en]
[s]
[vx]
Greenberg 2002
mean
duration
How Does the Brain Encode Modulation?
Neuroscience
Language
Representations
Networks
Neurons
Simple neural coding
mechanisms, like
oscillation at different
rhythmic rates, appear
to be critical.
Delta: 0.5 – 4 Hz
Theta: 4 – 8 Hz
Gamma: 20 – 50 Hz
The Brain Samples Information in Different
Frequency Bands (Theta, Gamma ..)
Speech signal
Rapid modulations
Gamma networks
20 – 50 Hz
Slow modulations
Theta networks
4 – 8 Hz
“syllables”
“phonemes”
Binding for
speech perception
Rise Times Enable Phase Locking?
Speech signal
Rapid modulations
Gamma networks
20 – 50 Hz
Phonetics:
ba - pa
Hickok, Poeppel
Alignment with
“edges” in signal
Slow modulations
Theta networks
4 – 8 Hz
Speech percept
Rhythm
Syllables
Meter
Hamalainen, Rupp et al. – Phase Locking
2 Hz
10 Hz
Early language experiences entrain the oscillators?
Speech signal
Perceptual
magnets
Infant-directed
speech
Rapid modulations
Gamma networks
20 – 50 Hz
Phonetics
ba - pa
Slow modulations
Theta networks
4 – 8 Hz
Speech percept
Rhythm
Syllables
Meter
Implications for Language Development
Prior to Schooling
Entraining the oscillators – activities that emphasise
rhythms and metrical structure of speech
-
nursery rhymes
poetry
music and singing
other rhythmic experience – dancing
marching
playing instruments
Link To Phonology:
Word Representations in the Brain
semantic
representation
phonological
motor
representation programme
Contribution of Brain Imaging
Brain
(mental lexicon)
Acoustic
signal
Phonology
How does the phonological system develop?
Need to understand how basic auditory processing
and learning to talk contribute to the development of
well-specified phonological representations
Phonological
Representation
What are the Brain Representations
of Language like Prior to Reading?
semantic
representation
phonological
motor
representation programme
The Mental Lexicon
Age 1 year
produce 50 – 100 words
Age 6 years
produce 6000 words
comprehend 14,000 words
Developmentally, requires fine-grained representations
of similarities and differences in sound
Spoken Language Processing
Lexicon
Phonetics
Phonology
Acoustics
Spoken Language Processing
Bottom-Up
Lexicon/
Reading
Phonetics
Phonology
Acoustics
Spoken Language Processing
Top-down
Lexicon
Phonetics
Phonology
Acoustics
The Development of Phonological Awareness
Children gradually become “aware” of sound
units within words as they develop their
language skills
A universal developmental sequence is found across
languages
Levels of Phonological Awareness
Syllable
(butterfly, wigwam, soap)
Rhyme
(onset-rime:
Phoneme
(smallest units of sound that change
meaning: cat-pat, cat-cot, cat-cap
but pin … spoon)
str - eet, fl - eet)
Basic Unit of Speech Processing – The Syllable
g ra s p
syllable
onset
gr
rime
phonemes
(develop largely via reading)
g
asp
r
a
s
p
The Development of Phonological Awareness
Oddity Task: Bradley & Bryant, 1983
Alliteration:
hill, pig, pin
Rhyme 1:
cot, hat, pot
Rhyme 2:
sit, pin, win
Oddity Task: English, German, Chinese
onset
rime
% correct
80
60
40
20
0
English
German
Chinese
Oddity Task: Dyslexic Children
(Bradley & Bryant, 1978)
Dys
RL
%correct
100
80
60
40
20
0
Allit
Rhyme1
Rhyme2
Adjusted stand score in months
Gains in Reading and Spelling after 2 yrs,
Adjusting for Age and I.Q.
Train
Ctrl1
Ctrl2
100
80
60
Read Acc
Read
Comp
Spell
Predicting Reading Acquisition
Language play
Nursery rhymes
Brain
Language
Phonology
Phonological
& orthographic
connections
Reading
“Auditory
Organization”
Measuring Syllable and Phoneme Awareness
e.g.,
tapping out sounds using a drumstick
counting out sounds using plastic tokens
Syllable level
popsicle
butter
soap
3 taps
2 taps
1 tap
Phoneme level
book
up
I
3 taps
2 taps
1 tap
Counting Tasks: Syllable vs Phoneme
phoneme
syllable
% correct
100
80
60
40
20
0
Nor
Ger
Fre
Tur
Gr
Rate of Phonemic Development
Languages vary in the degree to which letters have a 1:1
mapping to sound
Greek
Finnish
German
Italian
Spanish
Swedish
Dutch
Icelandic
Norwegian
French
Portuguese
Danish
English
Phoneme counting at end of Grade 1
% correct
Greek (Porpodas)
Italian (Cossu et al.)
Turkish (Durgunoglu & Oney)
German (Wimmer et al.)
Norwegian (Hoien et al.)
French (Demont & Gombert)
English (Perfetti et al.: Grade 2)
100
97
94
92
83
61
65
Predicting Reading Acquisition
Across Languages
Brain
Language
Phonology
Reading
Syllables
Rhymes
Phonemes
The Development of Phonological Representations
Infancy
- physical changes in signal where languages place
phonetic boundaries
- statistical learning of prototypes and phonotactics
- use of prosodic cues to segment syllables and words
 Within first year have proto-lexical representations
that encode stress and segmental information
The Development of Phonological Representations
Early Childhood
- enormous increase in vocabulary
- pressure for segmental specificity
- syllable structure varies across languages
- phonological “neighbourhood density” varies
across languages
How Reading Changes the Brain
PHONOLOGICAL
REPRESENTATIONS
OF WORDS
Speech-reading
eg, lip shape
Vocabulary size and
rate of expansion
Linguistic factors
eg, sonority profile
(language specific)
Speech processing
skills (input and
output)
Rhythmic cues
Syllable
Structure
(language
specific)
Word frequency/
familiarity/
age
of acquisition
Phonological
neighbourhood
density
(language specific)
Reading and spelling
acquisition
(phoneme level)
Vocabulary size and
rate of expansion
PHONOLOGICAL
REPRESENTATIONS
OF WORDS
chair tray tip
Speech-reading
eg, lip shape
Linguistic factors
eg, sonority profile
(language specific)
Speech processing
skills (input and
output)
Rhythmic cues?
Syllable
structure
(language
Specific)
Word frequency/
familiarity/
age
of acquisition
Phonological
neighbourhood
density
(language specific)
Development of Phonological Awareness:
Language Universal?
Preschool:
large units
syllables
rhymes
With schooling:
small units
phonemes
English Monosyllables: Approx. 4000
CV
sea
5%
CVC
cat
43%
CVCC
desk
21%
CCVC
trip
15%
CCVCC
grasp
6%
German: 1400
French: 2500
Representing Phonemes Varies Across Languages
Languages vary in the degree to which letters
have a 1:1 mapping to sound, and this affects
how rapidly phonology gets “re-mapped” in the brain
Greek
Finnish
German
Italian
Spanish
Swedish
Dutch
Icelandic
Norwegian
French
Portuguese
Danish
English
EU Study: Word and Nonword Reading (cvc)
NW "vuf"
Word "cup"
100
% correct
80
60
40
20
0
Gk Fin Ger
It
Sp Sw
Du
Ic
N
Fr
Po
Da Eng
Rates of development largely explained by spelling
transparency across languages
E.g., ‘a’
German
English
Hand
hand
Ball
ball
Garten
garden
Rates of Development across Languages
- development of phonemic representation slower
in less consistent orthographies
- development of grapheme-phoneme recoding skills
(“sine qua non” of reading acquisition) also
slower in less consistent orthographies
Educational Neuroscience
Importance of understanding how the
brain encodes information
Importance of understanding how environment
shapes the basic encoding
Focus on causal mechanisms of development
Deeper understanding of development
Implications for Language Development
Prior to Schooling
Need to hear as much language as possible
Importance of “rich” language
Rich language enhanced in story reading interactions
Entraining the oscillators – activities that emphasise
rhythms and metrical structure of speech
- nursery rhymes
- poetry
- music and singing
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