Phonetic details in prosodic phenomena Oliver Niebuhr Presentation at the Laboratoire de Phonétique...

Phonetic details in prosodic phenomena

Oliver Niebuhr

Presentation at the Laboratoire de Phonétique et Phonologie, Paris 3

January, 30th, 2009

[email protected]

• A number of attitudinal meanings are known to be signalled in German by prosodic means

• The speaker can convey that an information is– (a) “settled”, “concluding”– (b) “presenting”, “open(ing)”– (c) “astonishing”

• Furthermore, speaker can– (d) superordinate or– (e) subordinate her/himself to the dialogue partner

• The specific interpretations of these attitudinal meanings may vary depending on the semantic composition and the linguistic structure of the utterance

– In negative contexts (a) may be interpreted as “resignation” and (c) as “disbelieving / taken aback”

– (d) and (e) can convey ‘statement’ and ‘question’

Summary of German intonation (in terms of KIM)

• In the Kiel Intonation Model (KIM, Kohler 1991), these attitudinal meanings have been assigned to pitch-accent categories

• The KIM distinguishes between 2 basic phonological classes of pitch movements

– rising-falling peaks– G– (falling)-rising valleys

• Co-occur with accented (i.e. perceptually salient) syllables• Timing is phonological, not phonetic ( alignment) synchronization• Relevant according to Kohler (1987, 1991): F0 maximum (peaks) or

minimum (valleys) relative to the accented-vowel boundaries (onsets)


• ‘early’ peaks F0 max. before acc.Von = “settled”, “concl.” • ‘medial’ peaks F0 max. after acc.Von = “presenting” • ‘late’ peaks F0 max. after acc.Voff = “astonishing”

• ‘early/late’ valleys F0 min. before/afteracc.Von = “subordination” /

“questioning”

Did you hear me ??!

Answer: hmm…not exactly.Answer: yes, sure.


• The reference to the accented-vowel boundaries in the KIM originates from peak-shift experiments by Kohler (1987, 1991).

• On the other hand, his experiments showed that the location of the category boundary is shifted for different stimulus utterances (Kohler 1991)

– “Sie hat ja gelogen” = lateral + vowel – “Sie ist ja geritten” = fricative + vowel– “Sie hat ja gejodelt” = approximant + vowel

• Why?

earlier boundary

later boundary

The signalling of early, medial, and late peaks

Categorical changein perception‘early‘ ‘medial‘

Gradual change in perception‘medial‘ ‘late‘ around acc.Voff

• Niebuhr (2006, 2007c): maybe, it is not the segment boundary between C+V in terms of a spectral change (e.g., formant transitions) that matters, but the increasing / decreasing intensity into and out of the accented vowel

• The intensity change is more abrupt for sequences nasal+vowel or lateral+vowel than for approximant+vowel.

• It also depends on the vowel quality itself.• Starting from this idea,

– Two f0 peak shift series were resynthesized– One using the stimulus utterance “Sie war mal Malerin”– The other hand keeps exactly the F0 and intensity patterns of the “Malerin”

series, but on a constant Schwa-like vowel quality (= “HUM” in ‘praat’)– So, basically, the two stimulus series (“Malerin” and “HUM”) differ just with

regard to the presence / absence of the segmental string.– Two parallel perception experiments with two separate groups of subjects– Indirect identification for “Malerin” series– AXB test for “HUM” series


ContextStimulus

TestStimuli

Constant lexical stringConstant intonation

meaning

Constant lexical stringVariable intonation (iv)

meaning

Hearer / native speaker

Matching?

Indirect identificationof inton. categories

via meaning


“Malerin“ series


So, what happens, if wemanipulate the rising slopeof the intensity curve that reflects the CV transition?


Again two perception experiments, based on(a) “Malerin“ and (b) “HUM“ stimulus series.


– The dynamics of the perceptual change from ‘early’ to ‘medial’ decreases with decreasing dynamics of the underlying intensity change.

– The same effect shows up, if a less pointed F0 peak is shifted.

– A comparable effect of the dynamics of the F0 and intensity courses on the pitch-accent perception can be found for peak-shift series from ‘medial’ to ‘late’, based on a manipulation of the decreasing intensity at the VC boundary

“Malerin“series


• Conclusions of Niebuhr (2006, 2007c): The picture sketched by Kohler (1987, 1991) must be refined

– The abruptness of the perceptual changes between ‘early’, ‘medial’, and ‘late’ is not determined by the categories themselves.

– The change from ‘early’ to ‘medial’ can be turned into a gradual one The change from ‘medial’ to ‘late’ can be made categorical

– The signalling of ‘early’, ‘medial’, and ‘late’ is based on an interplay between F0 and intensity changes (or levels).

The findings support the central claim of the KIM that the synchronization of the (rising-falling) F0-peak contour relative to the vowel boundaries is decisive for the pitch-accent identification

– The findings can explain to some extent, why different alignment patterns of the F0 peaks are found for different structures and segmental compositions of the accent syllable and the adjacent syllables. They also make sense in terms of articulatory anchoring.



[j] vs. [m]

mmmOkay

Implication: Synchronization itself is not phonological; it is an effective, economic tool that speakers can use to highlight different parts of the pitch pattern by making use of the intensity pattern that results from the segmental string

• Alternative, complementary strategies: changing the overall peak shape, changing intensity levels, changing segment durations and articulations (e.g., openness of the vowel, sibilant / intrinsic pitch)


Impetus for looking at phonetic details (allophonic variations)of fricative and vowel segments in contexts of different

intonation categories

• Intonational difference in focus: phrase-final (nuclear) high-rising valleys vs. terminal falling peaks

• Segments (Phonemes) in focus:– Phrase-final //– Like /t/ aspiration, it can create “sibilant pitch” and is therefore particularly

likely to vary systematically according to the peak-valley difference.

– Moreover: // is realized in German with rounding []; this rounding does typically characterize already the preceding vowel → e.g., “Tisch” = [t].

• So, is // in the context of a high-rising valley lighter than in the context of a terminal falling peak? Is rounding involved in this effect? If so, then the effect should already be noticeable in the vowel preceding //.


Eine Ma le rin Eine Ma le rin


• Segments (Phonemes) in focus:– Phrase-final /x/

– It is also able to convey pitch by means of changes in the energy pattern of the noise spectrum

– Moreover: following /u/, /x/ is realized as a rounded velar fricative [x].• So, is /x/ in the context of a high-rising valley lighter than in the context of

a terminal falling peak? Is rounding involved in this effect? If so, then the effect should already be noticeable in the vowel /u/ preceding /x/.




• Segments (Phonemes) in focus:– Phrase-final <-er> word endings– It is realized as a vocoid sound [], which is known to show considerable

dialectal variation between [] and []• So, is it also influenced by the coinciding intonation categories? If so, is it

lighter (more fronted and/or open) in connection with high-rising valleys?– Phrase-final //– Its phonetic quality is known to be strongly context dependent in German

• So, is // lighter (more fronted and/or open) in connection with high-rising valleys?



• Pairs of target words (increases the ‘n’):– “Tisch”, “Fisch” → // with preceding //– “Buch”, “Tuch” → /x/ with preceding /u/– “lecker”, “Bäcker” → <-er> realized as []– “Tage”, “Schramme” → //

• Placed sentence- and hence phrase-finally in contexts of high-rising valleys and terminal falling peaks

• Acoustic analysis, including– F2 (based on LPC LTAS) at three points in the vowels: 20ms after onset,

centre, 20ms before offset– Centre-of-Gravity (CoG) determined every 7ms in the fricatives and then

averaged across the whole fricative segment.– Segment durations of vowels and fricatives


} “sibilant pitch“ } “intrinsic

} vowel pitch“

• Corpus recorded with quasi-spontaneous, informal sounding speech, using an improved method of Kohler und Niebuhr (2007)

• This means:• Written dialogue texts with informal, everyday contents/situations.• Target words are integrated sentence-finally without highlighting.• The high-rising valleys and terminal falling peaks as well as the

corresponding accented syllables are elicited solely by creating appropriate semantic-pragmatic contexts.

• Dialogues were produced by good friends.• They were allowed to modify the texts according to their own way of

speaking (e.g., by introducing or exchanging words and particles).• One of the speakers was the experimenter (me); he tried to guide the

subject with regard to speaking style, and his productions were part of the pragmatic context.

• Every dialogue was produced 4 times in a row, and only the last two productions were used for the acoustic analysis.

• So far, 5 subjects have been recorded (→ n=20), 10 are planned.


• Results for “Tisch” and “Fisch”• The sibilant // is considerably lighter in the contexts of the high-rising

valley. This is reflected in significantly different mean CoG values. The fricative durations, however, do not differ significantly.

• Also the productions of // differ depending on the intonation context. That is, F2 (middle) is significantly higher after the high-rising valley.

• Supported by perceptual analysis, this effect involves de-rounding.

peak valley


• Results for “Buch” and “Tuch”• The fricative /x/ is considerably lighter in the contexts of the high-rising

valley. This is reflected in significantly different mean CoG values. The fricative durations, however, do not differ significantly.

• Also the productions of /u/ differ slightly in the way that the F2 (middle) tends to be higher after the high-rising valley.

• Supported by perceptual analysis, this is again due to de-rounding.


peak valley

peak

valley

• Results for “lecker” and “Bäcker”• The vocoid realizations of the word ending <-er> are not consistently

lighter in connection with the high-rising valley. Such an effect – i.e. a higher F2 – can only be observed in tendency towards the end of the sound.

in connection with the high-rising valley <-er> becomes a diphthongized [], which also tends to be longer than in connection of the terminal falling peak.

650 1650700 1300

peak valley


• Results for “Tage” and “Schramme”• The productions of // are lighter, i.e. they show a significantly higher

F2 at the centre and towards the end of the vowel in connection with the high-rising valley.

• However, the vowel durations do not differ significantly depending on the intonational context.

600 1200 650 1750

peak valley


• We know that the F0 course contributes to the coding of segments• F0 rise or fall before/after obstruents is a fortis-lenis cue (Kohler 1979)• F0 relative to F1 determines the vowel quality (Traunmüller 1985)• Position of F0 turning points cues word boundaries (D‘Imperio 2000,Petrone 2008)• (...)

Lexemes and PhonemesIntonation

Summary of the intonational part

• We need not forget that the segmental string is not (just) a „troublemaker“ for the coding of intonational units• The segmental contribution can the of two different kinds:

• direct: e.g., by intensity-based highlighting of parts of the F0 course, by conveying different sibilant or intrinsic (i.e. vowel-based) pitches• indirect: e.g., by articulatory metaphers of attitudinal meanings, i.e. long, soft, and light articulations for astonishment vs. short, loud, dark articulations for conclusions or superordinations, etc.

Lexeme, Phoneme, PhoneIntonation

!Summary of the intonational part

• Based on a recent investigation of Niebuhr et al. (2008) within the S2S research network

• Starting from a corpus of read speech that comprised 72 sentences that may be subdivided into three subsets

– (1) the 8 possible sibilant sequences across word boundaries that result from the cross-combination of the features 'alveolar', 'postalveolar' and 'voiced', 'voiceless', i.e. (a) /s/, (b) /s/, (c) /z/, (d) /z/, (e) /s/, (f) /s/, (g) /z/, and (h) /z/ placed in the symmetrical vowel contexts /i/___/i/, /a/___/a/, and /u/___/u/ (= 24).

– (2) (a) /s/, (b) /s/, (c) /z/, (d) /z/ framed by the 6 asymmetrical vowel contexts (= 24).

– (3) each of the 4 individual sibilants /s/, //, /z/, and // paired across word boundaries with a labial consonant (C) like /p/ or /v/ in the two possible orders __C and C__ and framed by symmetrical vowel contexts reference qualities for the sibilants (=24).

– All 72 sentences were read 4 times in a randomized order by 4 female native speakers of French

Place assimilation in French sibilant sequences

• Based on a recent investigation of Niebuhr et al. (2008) within the S2S research network

• Starting from a corpus of read speech that comprised 72 sentences that may be subdivided into three subsets

– (1) /usu/: “Tu te couches sous l'drap”– (2) /asa/: “C'est une classe chargée”

– (3) /uzu/: “J'ai vendu douze journaux” – (4) /aza/: “C'est une phrase japonaise”

– (5) /aCa/: “Tu te caches facilement”– (6) /izCi/: “Il a une devise vitale”– (7) /aCsa/: “Elle tape sa soeur”


• Measurements:• Spectral:

– range and mean

of the CoG across

the whole section• Duration

– of the whole section

– of the individual

sibilants were

possible


• Results in the temporal domain:• If there were two spectrally separable sibilant sections, the postalveolar

was always the longer one.• Overall, the

sequences

were around

twice as long

as the single

references,

alv.-postalv.

in tendency

even more

than

postalv.-alv.


• Results in the frequency domain:• The alveolar-postalveolar as well as the postalveolar-alveolar sequences

were both spectrally

shifted in a comparable

way towards the

postalveolar references.


• Conclusions:• Place assimilation in French sibilant sequences is a gradual rather than

a categorical phenomenon• It is feature-determined, not direction-determined. The target is

postalveolar. Consequently, it is regressive in alveolar-postalveolar and progressive in postalveolar-alveolar sequences.

“Elle remâche sa viande” : /s/ [:] “C’est une classe chargée” : /s/ [:]

• The assimilated alveolar-postalveolar and postalveolar-alveolar sequences can have phonetically identical manifestations in terms of both temporal and spectral values.

• But are these sequences really ambiguous?


• Nolan (1992) found for English that word-final /d/s which were completely assimilated to following word-initial /g/s (in terms of EPG patterns) were still identified as /d/s by his subjects.

• He ascribed this effect to differences in the preceding vowel.

• Starting from this interesting observation, which was not further pursued so far, we investigated whether the vowels that preceded the assimilated /s/ and /s/ sibilant sequences in French show differences in phonetic details that can be used by listeners to identify the even those following sibilant sequences as /s/ or /s/ that are ambiguously realized as [:].


• This is what we found for vowel duration and vowel intensity:– The vowels /a, i, u/ were significantly longer when they preceded /s/ (on

average 15-20ms, up to 60ms).– The vowels /a, i, u/ were significantly louder when they preceded /s/ (on

average 2-3dB, up to 5dB).


0

10

20

30

40

50

60

70

80

90

100

a i u

Dura

tion (m

s) ..

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

Ave

rage

RM

S (dB

) ..

a i u

• And in addition we found for voice quality:– The vowels /a, i, u/ were significantly breathier when preceded by /s/.– The voice quality was represented by the harmonic ratios H1/H2, based on

narrow band DFT spectral at three points in the vowel: 20ms after onset, centre, 20ms before offset.

– On the other hand, the vowels before /s/ sometimes show a short section of /h/-like friction before the actual sibilant sets in (= different timing of breath?)



160ms

160ms

43ms

65ms21dB vs. 17dB

/s/

/s/


170ms

150ms

49ms

57ms18dB vs. 16dB

/s/

/s/

• Initial perceptual tests were done in which (a) just the CV part of the first target syllable and (b) just the sibilant section itself was played to non-naïve native speakers of French. The preliminary results show that the listeners were only able for (a) to predict beyond change level whether the upcoming sibilant sequence was /s/ or /s/.

• So, the multi-parametric phonetic details in the vowels preceding the sibilant sequences might already be acoustic cues to the phonological make-up of the sibilant sequence, even if the phonetic realization of the latter is by itself ambiguous.

• This suggests that the term “gradual” has a temporal implication beyond the sibilant sequence itself.

• Moreover, the fine phonetic differences in the vowels were not found in the same way before single, non-assimilated sibilant. This might be taken as evidence that place assimilation within French sibilant sequences represents a re-organization rather than a (gradual) substitution of phonological features, in line with previous findings of many other assimilation processes across languages.

Summary of the assimilation part

Phonetic details in prosodic phenomena Oliver Niebuhr Presentation at the Laboratoire de Phonétique...

Documents

Transcript of Phonetic details in prosodic phenomena Oliver Niebuhr Presentation at the Laboratoire de Phonétique...