THE INTERACTION OF STATISTICS AND PHRASAL PROSODY
BUDAPEST
SEPTEMBER 23-25
THE MOUTH
JACQUES MEHLER
THE BRAINS
MOHINISH
MARINA
SHUKLA
NESPOR
EXPERIMENTS HAVE SHOWN THAT 8-MONTH OLDS USE
STATISTICS TO SEGMENT SPEECH STREAMS
SYLLABLES AND CONSONANTS, BUT NOT VOWELS, ARE THE
NATURAL INPUTS TO SUCH COMPUTATIONS
THUS, ARGUING THAT STATS ARE THE ONLY ENGINE TO LEARN
LANGUAGE FAILS TO SPECIFY THE INFORMATION KINDS THAT
SERVE AS INPUT TO STATISTICAL COMPUTATIONS
SPECIFIC INPUT CATEGORIES ARE USED WHILE OTHERS ARE
NOT
WE HAVE ALSO SHOWN THAT UNDER SLIGHLY
SIMILAR EXPERIMENTAL CONDITIONS PARTICIPANTS
DRAW CONJECTURES ABOUT THE STRUCTURAL
RELATIONS THAT MIGHT HOLD FOR THE CORPUS
ITEMS’
DO THE TWO MECHANISMS, STATS AND SYMBOLIC
RULES WORK AUTOMATICALLY OR CAN ONE OF THEM
BE INHIBITED BY THE OTHER?
• HOW DOES THE OUTPUT OF ONE MECHANISMS OR
COMPUTATION INTERACT WITH THAT OF THE OTHER?
CAN TP COMPUTATION BE STOPPED OR
CONSTRAINED BY SOME OTHER PROPERTY OF THE
SIGNAL?
NSTURAL SPEECH IS NEVER PRODUCED AS AN
HOMOGNENEOUS STREAM. UNIVERSALLY, ALL
LANGUAGES USE PHRASAL PROSODY AND OTHER
PROPERIES TO MAKE STREAMS SOUND “NATURAL”.
MOHINISH SHUKLA
CARRIED OUT WORK TO OBTAIN A PH.D. AT SISSA
HE ASKED: CAN STATISTICAL COMPUTATIONS BE
SUPPRESSED OR AT LEAST CONSTRAINED BY OTHER
SPECIFIC SIGNALS
SHUKLA USED SPEECH STREAMS. HIS FIRST
STREAM INCORPORATES PROSODIC INFORMATION
IN THE SEQUENCES OF SYLLABLES
Contrasting Contour-Internal and ContourStraddling ’words’.
overlaid prosodic contour
CI
10 SYLLABLE FRAMES
CS
CI : Contour-internal word
CS : Contour-straddling word
ITALIAN PARTICIPANTS WERE FAMILIARIZED
FOR EIGHT MINUTES
PROSODIC CONTOUTS USED WERE TYPICAL PATTERS
EXISTING IN ITALIAN
AFTER FAMILIARIZATION PARTICIPANTS WERE PRESENTED
PAIRS OF ITEMS AND SAY WHICH ONE WAS MORE FAMILIAR
ONE ITEM WAS AN ACTUAL “WORD” THE OTHER A “PARTWORD”
COURTESY: M. SHUKLA – 8min familiarization
Contrasting Contour-Internal and Contour-Straddling
’words’.
CI
CS
Single ‘frame’ of 10 syllables
COURTESY: M. SHUKLA
CI : Contour-internal word
CS : Contour-straddling word
CONTROL WITHOUT PROSODIC COUNTOURS
COURTESY: M. SHUKLA
AS CONTRAST TO THE PREVIOUS EXPERIMENT, THE CONTOUR
STRADDLING ITEM IS NO LONGER RECOGNIZED
WHILE THE CONTOUR INTERNAL WORD CONTINUES TO
BE RECOGNIZED
ARE THERE OTHER POSITIONS WHICH
WOULD FARE EVEN BETTER WHEN COMPARED WITH
THE CONTOUR INTERNAL WORDS?
WE KNOW THAT EDGES ARE PERCEPTUALLY AND
MNEMONICALLY SALIENT. WHAT WOULD BE THE FATE
OF A STRADDLER WHICH WOULD BE MOVED TO ONE OF
THE PROSODIC EDGES?
Contrasting Contour-Edge and Contour-Middle ‘words’.
overlaid prosodic contour
E
M
E : ‘Edge’ word
M : ‘Middle’ word
COURTESY: M. SHUKLA
LEFT EDGE VERSUS MIDDLE
COURTESY: M. SHUKLA – 4min familiarization
RIGHT EDGE VERSUS MIDDLE
SHUKLA NEST QUESTIONED WHETHER THERE TRACES
OF STRADDLES EXIST, SHOWING THAT STATISTICAL
COMPUTATIONS HAD TAKEN PLACE BUT WERE THEN
FILTERED BY THE OVERLAY OF PROSODY?
IS IT THE CASE THAT PROSODY DELIMITS THE DOMAIN
OF TPs COMPUTATIONS OR ARE TPs COMPUTATIONS
CARRIED OUT OVER THE WHOLE STREAM BUT PROSODY
FILTERS OUT STRADDLES AS BEING BADLY FORMED
IT IS UNCLEAR HOW TO DESIGN AN EXPERIMENT
TO CHOSE BETWEEN THESE TWO MECHANISMS
SHUKLA DECIDED TO PRESENT WORDS AS THEY WOULD
HAVE BEEN REPRESENTED IN THE OUTPUT BUFFER THAT
COMPUTES SYLL. TPs. TO DO THIS HE DECIDED
TO PRESENT THE WORDS IN WRITTEN FORM
FOUR MINUTES FAMILIARIZATION
Japanese IPs
Internal: 73.21%, p<0.001
Straddling: 41.96%, p=0.057
Internal vs Straddling: p<0.0001
Japanese IPs:
Left edge vs middle
Left Edge: 74.11%, p<0.001
Middle: 44.64%, p=0.43
Edge vs Middle: p<0.01
Japanese IPs:
Right edge vs middle
Right Edge: 65.63%, p<0.05
Middle: 47.92%, p=0.71
Edge vs Middle: p<0.05
THESE RESULTS SUGGESTS THAT TRACES
OF THE INCIPIENT PROCESS OF TP. COMPUTATIONS CAN
BE OBSERVED SUGGESTING THAT PROSODY DOES NOT
DEFINE TP DOMAINS
YET, THOUGH SHUKLA’S EXPERIMENTS ARE
INTERESTING THEY OUGHT TO BE STRENGTHENED
IF WE ARE GOING TO TAKE THE AUTOMATICITY AS
A “FAIT ACCOMPLI”
A CHALLLENGE WOULD BE TO DESIGN OTHER MEANS
UNDER WHICH THE COMPUTATIONS OF TPs CAN BE
INHIBITED