Getting at variation with ultrasound: Scottish and Dutch r

1
Getting at variation with ultrasound Scottish
and Dutch /r/

• Ultrafest 3University of Arizona at Tucson
• 14-16 April 2005
• James M Scobbie (QMUC)Koen Sebregts
  (Utrecht)and thanks also esp. to Alan Wrench and
  Yolanda Vasquez Alvarez

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Why /r/? Why ultrasound?

• Previous articulatory studies of /r/
• There is a lot of variation
• Variation, change, acquisition, phonetics
• labiodentalisation of /r/ in Anglo English
• vocalisation of final /r/ in Scottish English
• retroflexion of final /r/ in Dutch
• Phonology what is an /r/ anyway?
• Ultrasound
• Relatively informal
• Can provide dynamic images

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Can we add to MRI?

• Tiedes beautiful images (from ICPhS 03)

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Can we add to MRI?

• And perhaps what we can expect

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Can we add to MRI?

• And perhaps what we can expect

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Can we add to MRI?

• Tiedes beautiful images (from ICPhS 03)

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Problems with ultrasound

• The usual
• Incomplete images, no passive articulator
• Head-probe correction or control
• Synchronisation and low frame rate
• Splines and edges
• Stats
• plus
• European video output (PAL) is at 25Hz (albeit
  with more pixels, esp in raw AVI)
• Fieldwork taped data is slower to prepare

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Data collection the laboratory

• Good
• Helmet (or other head games)
• Less environmental noise
• The experimenter is in control
• Choice of equipment and software - demo
• but
• Willing and normal subjects have to be found
• Experiment costs
• Intimidation of subjects

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Data collection the field

• In this case Glasgow Science Centre
• Good
• Lots of varied and willing subjects
• Outreach and publicity (!)
• Vernacular speech more elicitable
• Qualitative articulatory transcription - demo
• but
• Things are a little out of control (cf feedback)
• Small amount of time for each subject
• Non-ideal equipment and methodology

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What do we want for /r/?

• Varied vowel environments
• Varied word and syllabic positions
• Acoustic analysis (and other channels?)
• Info on multiple articulators
• Stratified pool of subjects
• Normal vernacular speech
• Dynamics
• Synchronised data

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Backstep methodological issues

• Smearing of raw data due to scan rate
• Creating of video output - downsampling and
  synchronisation problems

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Matrix of raw data generated at the scan rate of
the ultrasound machine e.g 72 complete scans per
second
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Methodological issues

• There is always a delay
• Our range was 20ms to 100ms (mean 40ms)
• Does our 25Hz rate make it clearer or worse?
• Practicalities
• Multichannel synchonisation, even video, even
  acoustics, is based on unpredicatable delay
  whether via camcorder or direct
• Individual video frames can be arbitrarily split
  in addition to overlay and interlacing
• High ultrasound sample rate alone is not enough

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Scottish background

• Field work in Glasgow Science Centre
• Stuart-Smith et al discover heavily retracted
  coda /r/ in young (teenage) vernacular Scots
• Not vocalisation like middle class
  Anglification
• Strong breaking (transitioning) with limited time
  at target?
• Different target?
• Limited evidence of mergers (yet)

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Scottish pilot

• Methodological
• Probability of numerous subjects (hundreds)
• All age groups, wide spectrum of social mix
• Handheld probe plus mike mix to tape
• Eyeball qualitative analysis is highly feasible
• Need lab-based follow-up for quantitative
  research
• Descriptive so far (very sketchy!)
• Clear and obvious cases of pharyngeal /r/
• No meta-linguistic awareness of change

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Scottish hypotheses implications

• Strong breaking in coda is a strong pharyngeal or
  tongue dorsal gesture
• Some speakers have lost any obvious anterior
  gesture in coda
• Anterior gestures, if present, include retroflex
  and bunched types of /r/
• This is socially stratified
• There should be intra-speaker variation too
• How categorical are these variations?
• We need representative dynamic data

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Dutch background

• Large sociolinguistic, phonetic and phonological
  survey of Dutch (van Hout, Zonneveld and Van der
  Velde)
• 400 subjects in multiple locations in Netherlands
• Some speakers have uvular trill/fricative /r/ in
  onset, and an anterior approximant in codas
• What is going on articulatorily?
• What is the inter-speaker sub-variation like?

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Dutch study

• Subjects
• 10 all in Edinburgh
• Post-screened down to 4 anterior /r/ users
• Materials and protocol
• Picture naming (n lt 30)
• Real words, near minimal pairs /ir/ /ur/ /ar/
• Singleton /r/ and cluster /r/ and /r/-less
• 3 reps
• Feedback
• Unaware of focus on /r/

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Dutch study

• Target its a multi gestural thing
• How do we choose the right frame for /r/?
• Using acoustics needs good synchronisation
• Using the images themselves is circular
• Intergestural timing at 25Hz?
• Dynamics
• How to characterise?
• Acoustics
• Same sort of questions target dynamics
• Final devoicing

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Boer MS point is red at end of voice tip down
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• Boer 1 RB

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Boer 2 RB
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Boer 3 RB
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Mier 1 RB
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Mier 2 RB
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Mier 3 RB
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Schaar 1 RB
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Schaar 2 RB
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Schaar 3 RB
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Boer 2 RB
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boer 2 vdl
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boer 2 VDB
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boer 2 MS
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So far

• Visual inspection of raw images or dynamic spline
  diagrams
• Two retroflexers (RB VDL)
• Two bunchers (MS VDB)

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Next

• Acoustic identification of an r phase
• Midpoint spline can be extracted
• No discrimination of voiced or voiceless
• Identification of single max rhotic is similar
• Acoustic analysis
• Steady-state V transition r-phase
• Location of end of voicing
• F2 F3 of voiced (usually) r target if obvious

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• MS bunched mainly voiced

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• VDB bunched mainly voiced

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• RB retroflex mainly voiceless

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• VDL retroflex-ish but nearly vocalised?

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• VDL real non-rhotic vowels for comparison
• boer vs. koe
• mier vs. riem
• schaar vs. sla

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Dutch summary

• 4 speakers with anterior coda /r/
• Two retroflex
• Two bunch
• One of the retroflex speakers is gradiently
  vocalising
• Timing the /r/ late before pause
• But some long domain cues in vowel quality and
  consonant variation
• RB has strong transitions too rather than steady
  state but ?? sounds more rhotic
• Interesting to look at following C

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Overall summary

• Dutch anterior /r/ has various flavours
• Retroflex
• Non-retroflex
• Weakened and late pre-pausal gesture
• Glasgow /r/ comes in various flavours
• Pharyngeal approximant observed
• Breaking taking over from rhoticity
• Strong phonetic effects
• Vulnerable non-standard speech
• Socially-stratified qualitative UTI is T.o.C.

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Conclusions, implications

• Weakening of final /r/ is flexible
• Multiple articulators provide lots of options
• Strength and timing are affected
• Effects can be gradient and/or categorical
• Acoustic effects appear complex
• Phonological contrasts need not be affected
• Small (?) sub-phonemic effects, change, and
  variation go hand-in-hand
• Fine detail and structured variation are in the
  grammar

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Methodology field solution

• Splines and edges lose a lot of info
• Relative to MRI X-ray etc
• Relative to ultrasound images
• Qualitative analysis of images usefully augments
  impressionistic transcription
• This can be done live and/or from tapes made in
  the field
• Small amounts of data from large numbers of
  subjects is standard practice

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Methodology lab solution 1

• Dedicated hardware software in the lab

Matrix of raw data time stamped at headline
sample rate (100Hz) Image processing
Audio etc Time stamped
PC buffer files
Start

• High speed, synchronised, clean images
• Integrated analysis (spline fit, export etc)

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Methodology lab solution 2

• Multichannel backbone (incl 200Hz EPG)
• Funding application submitted
• 100Hz synchronised machine ( EPG)
• Multichannel developments (EMA, VICON)
• Helmet improvements
• Also, funding application submitted for ultrafest
  5 (2007)

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Holiday report

• Excellent!

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Demo of lab data collection

• Slide 8
• AA