Failed, because: Discriminability alone is not enough; code on speech needs to be compatible with speech. Minimally, must have the speed of speech.

Lessons: A useful reading machine would have to (i) produce speech, (ii) be based on letter identity, not shape

scan text with stylus, arbitrary complex sounds, 1 per letter shape

The Challenge of a Reading Machine for the Blind (1944)

optophone

Reading machine conception, 1969

Frequency (Hz)

Time (s)

The spectrogram and the pattern-playback

Context-conditioned variability of speech perception

Nothing means something

Different things mean the same thing

The same thing means different things

context-conditioned variability

originally the problem, ultimately the solution

a

b

g

time

ƒreq

uen

cy

“BAG”

Co-articulation of gestures produces acoustic variability

Is speech perceived by reference to how it is produced?

 

Invariance is in articulation, not acoustics 

Object of perception is gesture, not sound

producing any single phoneme involves ≈ 70

motor invariance must be abstract given that motor commands are variable

70 muscles of speech

articulation

phonation

respiration

Dynamics of self-organization, intrinsic timing, articulatory phonology Basic phonological unit: articulatory

gesture, a dynamical system with a characteristic set of parameter values.

tract variables articulators

constrictions variable in location, degree

“planning” dynamics

“execution” dynamicscoordinate

transformation

An utterance: an ensemble of potentially overlapping gestural units

intended gestures

articulatory dynamics

perceive gestures

[Phonetic Module]

habituation continues

habituation dishabituation

No. of Sucks per minute

Time

3 mos

Categorical Speech Perception in Infants

Initial babbling: all phonemes (Dutch, Zulu, Farsi, …)

La La La

1st year

Ra RaLa La

8 mos

No. of Sucks per minute

Time

La La La Ra RaLa La

habituation

•Experiment with Japanese babies:

•Growing sensitivity to native phonemes and insensitivity to non-native phonemes

La ≠ Ra

La Ra

Can’t distinguish letters, a visual perception problem?

Can’t register order of letters and words, a visual representation problem?

Can’t scan letters and words properly, an eye control problem?

Why might a child have difficulty reading?

Can’t hear the sound contrasts that distinguish words, an auditory perception problem?

Can’t link letters to their speech sounds, an associative learning problem?

Can’t learn the spelling rules, an (English) orthography problem?

/b/

/a/

/g/

“BAG”

time

ƒreq

uen

cy

sound energy

/a/ throughout /b/ first 2/3 /g/ last 2/3

/a/, /b/, /g/ overlap in middle

Haskins’s answer:reading is hard

because speech is easy

Can’t explicitly segment words into phonemes, a phonological awareness problem?

Would-be-reader’s challenge: Gain awareness that spoken words break apart into distinct abstract segments (phonemes)Then: Has basis for learning that letters stand for phonemes—the meaningless elements that make up the words of the spoken language. The Alphabet Principle

Does phonology’s role in reading depend on the writing system? (orthographic depth hypothesis; Serbo-Croatian, Hebrew, English,

Chinese)

Phonological Coherence HypothesisUniversal Phonological Principle

word or

nonword?

fluent bi-alphabetical reader

component circuits, hypothesized roles

phonological

sem

antic

visual word form

Can we reveal the reading network through fMRI and related tools?

Can we reveal improvement in an under-engaged network with training?

Normal

Dyslexic

rhyming task

phonological

training

Most of the major suspects!