Ultrasoundbased tongue root imaging and measurement

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Ultrasound-based tongue root imaging and
measurement

• James M Scobbie
• QMU

With thanks to collaborators Jane Stuart-Smith,
Marianne Pouplier, Alan Wrench, Eleanor Lawson,
Olga Gordeeva
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Introduction

• Pros and cons of Ultrasound Tongue Imaging
• EPG/UTI experiment on English /l/
• Alveolar contact or vocalisation
• Light and dark allophones of /l/
• The ECB08 UTI corpus
• Scottish derhoticisation and articulation of /r/
• Vowel system
• A handful of /l/ again
• Demo of AAA software

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UTI

• From qualitative transcription to quantitative
  laboratory-based studies with stabilisation

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Pros and cons of UTI

• Pro
• Tongue root to blade in one image
• Instant, real-time, easy, safe, cheap
• Qualitative and quantitative analysis
• Can be combined with other techniques
• Con
• Image quality is variable
• Hardly any constriction or info on passive
  articulator
• Frame rate of video output is only 30Hz (33ms)
• Synchronisation with acoustics is problematic
• Quantitative analysis is time-consuming and as
  yet poorly developed what to measure?

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Future corrected high speed data
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English /l/

• /l/ is lighter in onset, darker in coda
• Many accents have vocalisation in coda
• EPG UTI study of 10 speakers
• UTI image quality uniformly awful ?
• EPG results very interesting ?
• Context was /i//l/ ( /b/, /h/, /l/) /i/
• Pee leewards, peel beavers, peel heaps of, etc.
• EPG results
• Reduction or loss of alveolar contact in codas
• Reduced palatal contact (compared to /i/) due to
  /l/

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Example onset

• Alveolar contact in orange, palatal in green
• S2 typical in losing palatal contact in
  onset(can we pee leewardin a gentlebreeze)

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Example coda_b retraction

• No alveolar contact, more palatal contact (can
  we peel BBC advertisingfrom the shop window)

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EPG results loss of palatal contact

• E S1 light onset and dark coda in palatality
• Scots S2,3,4 show darker (less i-like) onset
• Question 1 what about intergestural timing?
• Question 2 what about the pharyngeal aspect of
  darkness rather than loss of palatality?

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EPG results timing

• Relatively simultaneous alveolar contact and loss
  of palatality in onset
• Alveolar contact is delayed in coda (or missing)
  and loss of palatality occurs earlier

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Coda vocalised and darker
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UTI Scottish pharyngealisation?

• Measurement of Tongue root retraction in i and
  in l for a single sample speaker S2
• Coping with terrible quality UTI
• Find frames of maximum advancement and maximum
  retraction of root just above hyoid shadow)
• Typical problems in measuring images

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Example onset

• Poor image quality
• Time and location of root top of hyoid shadow

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Example onset

• This is only a bit better than guessing, but
  impression is of slight pharyngealisation

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Results (S2, n 18)

• Tongue root retracts earlier in coda_b (plt0.01)
• Max advancement appears to be near end of i
  vowel in onset condition and mid-way through i
  in coda_b condition
• Max retraction apparently at end of l in onset
  condition and towards the end of b in coda_b
  condition
• i is less advanced in coda_b than onset
  (plt0.005)
• There is a n.s. trend for greater
  pharyngealisation in coda l

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Conclusions

• Darkness as measured by decrease in palatality in
  /i/ context shows onset/coda differences for only
  some speakers
• Probably dialectal Scots /l/ is less i-like in
  onset
• All speakers show a strong timing difference
• Front and back gestures dissociate in coda so
  that posterior gesture is earlier and alveolar
  (if present at all in coda) is later (gestural
  dissociation)
• Qualitative (and quantitative) analysis of UTI
  data probably shows greater pharyngealisation for
  all speakers coda than onset.

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ECB08

• Ultrasound/acoustic corpus
• 15 teenagers (12-14) in friendship pairs (4
  11yrs)
• Wordlist and some spontaneous discourse
• Half from a WC and half from a MC school
• Main purpose to test effect of use of UTI on
  vernacular speech variables
• Secondary purpose
• Derhoticisation of coda /r/ - pharyngealisation?
• Vowel space
• But sadly not much room for
• Vocalisation of coda /l/ - pharyngealisation?

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Derhoticised coda /r/

• Hiya my name's Kaj McInally
• My company's FinesseDecor (Scotland) Ltd
• I'm not a manager. I'm a painter and decorator
• to trade, first and foremost
• who just so happened to start work for myself,
  and then
• weve been that... kinda... successful that we've
  had to take on people

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Losing /r/ in Scotland

• Since the 1970s coda /r/-loss has been reported
  in working class speech
• Not the RP-like middle-class non-rhoticity
• Stuart-Smith (2003) in a Glasgow corpus including
  14-15 year old children showed that WC girls have
  no overtly rhotic consonant for coda /r/ in
  approximately 90 of cases, boys in about 80
• Middle class children and older adults are
  rhotic, so the stratified derhoticisation is
  indicative of change in progress.
• /r/ seems to be turning into a vowel right now
• Strong impression of pharyngealisation offglide
  on vowels with monophthongal pharyngealisation on
  low back ones

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rain, with an anterior approximant, usually
described as being retroflex (note low F3)
ferry, with a tap (an approximant is more common)
Typically rhotic tokens of Scottish /r/
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Word-final derhoticisation in ECB08
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Rhotic (MC) speakers

• Lexical sets BIRD WORD HERD merged (8/11)
• Earth, verb, berth, (err) third, word, surf,
  birth, fur
• Could be a rhotic vowel /?/
• No /a/ split (Pam/palm are homophones)
• /?/ is central and not very high

i? ?? o? e? ? ?? ??
i ? o e i ? ? a
?
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MC Edinburgh
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WC West Lothian
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Articulation of vowels (EF4)

• Phonologically, only /? I ?/ are lax

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Sample ultrasound images of /r/

• Tipup (LM17 onset) or tipdown (LM15 onset)

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Waterfall time sequence hair
?
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Derhoticising (WC) speakers

• More vowels (and environments) with weak /r/
• No merger of /?r/ and /?r/ (8/8)
• /a/ split (hat/heart) a vs. ? for the most
  derhotic
• /?r/ is short without compensatory lengthening
• High vowels create diphthongs
• Pre-pausal /r/ tends to devoice
• Potential /?/ merger (hut/hurt, bud/bird)

i? ?? o? e? ?? ?? ?? ?(?)
i ? o e i ? ? a
?
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Pre-pausal /r/ may have late (covert?) tip

• Low vowels sound derhoticised, acoustically lack
  F2/F3 approximation, and are near-monophthongs.

• Articulatorily a clear rhotic gesture was
  retained

car
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Covert rhoticity occurs even in weak syllables
and in spontaneous speech
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/l/ in a derhoticising (WC) speaker

• What about /l/?
• If dark, is it pharyngealised?
• If vocalised, is it a pharyngeal?
• How are derhoticised /r/ vocalised /l/ kept
  apart?
• Hip hum hut
• Fur/fir hurt
• Pill film
• Mull bulb cult
• Clear difference between /r/ and /l/ in open and
  closed syllables

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UTI of laterals

• Red /?/ mull (cons) bulb (vocalised)
• Blue /i/ film (cons) pill (vocalised)
• Pharyngealisation vs. velarisation?

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UTI of laterals

• Red cult (cons /lt/)
• Green hurt (cons /t/)
• /l/ pharyngealised velarised?
• Pharyngealised postalveolar /r/ with saddle

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/l/ compared to /o/ and /?/

• Pharyngealisation and velarisation more extreme
  than in vowels

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Conclusions

• Onset/coda differences in /l/ in a high vowel
  context are well-known to involve loss of
  palatality and a greater pharyngeal constriction
  (Sproat and Fujimura 1993), plus subtle loss of
  alveolar contact (eg Giles Moll)
• Scottish speakers who have no onset/coda
  difference in palatality do show increased
  pharyngealisation in coda (and may show very
  strong vocalisation, not gestural undershoot)
• Vocalised /l/ may be velarised while
  pharyngealisation occurs for consonantal /l/

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Conclusions

• Derhoticisation often sounds like
  pharyngealisation
• But in prepausal and other masking contexts there
  can be delayed covert post-alveolar constriction,
  due to gestural dissociation
• WC /r/ seems to be changing from consonant into
  vowel, with some increase in vowel space
• Meanwhile, MC rhotic speakers merge vowels
• WC /l/ and /r/ seem to be keeping distinct
• Is the pharyngealised /l/ also velarised?
• Is the difference purely anterior?

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AAA demo

• Lets look at pharyngealisation in a
  derhoticising speaker
• Hut vs. hurt
• Bud vs. bird
• Far vs. fir

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Who says you need ultrasound?