PHARYNGEALIZATION of EAST THURINGIAN POSTVOCALIC /R/: ARTICULATION, ACOUSTICS and TEMPORAL EXTENT
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PHARYNGEALIZATION OF EAST THURINGIAN POSTVOCALIC /r/: ARTICULATION, ACOUSTICS AND TEMPORAL EXTENT Christina Otto & Adrian P. Simpson Institute of German Linguistics, Friedrich Schiller University Jena [email protected]; [email protected] ABSTRACT sively e.g. in varietes of Arabic [2, 1, 13, 10], ar- ticulatory or acoustic studies on east German vari- This study investigates the acoustic and articulatory eties are scarce [11]. An earlier analyis of the UTI influence of postvocalic /r/ on the realization of vow- data presented here was able to confirm the influ- els in an east central german variety. A selection of ence of /r/ on the tongue contour configuration as /r/ and /r/-less word pairs containing the short vow- both retracted and lowered and on acoustic output els /Y E a O U/ of seven male speakers were recorded (F1 raised, F2 lowered) in target words with postvo- using Ultrasound Tongue Imanging (UTI). System- calic /r/ in comparison to target words without /r/ atic differences were found both in lingual config- [19]. East Thuringian belongs to the east central urations as well as spectral measures (F1-F3) con- German dialect group Thuringia-Upper Saxon and sistent with pharyngeal constriction. Especially the is spoken in the east of Thuringia and south west- articulatory analysis of a greater portion of the word ern Saxony-Anhalt and is mostly a transition zone indicates consequences of /r/ having greater tempo- to Upper Saxon [23]. ral extent showing /r/ to be a feature of the entire While the initial study concentrated on a qualita- syllable rather than of a single segment. tive analysis and visual description of tongue con- tours, the aim of the present study is to quantify the Keywords: Ultrasound, East Thuringian, /r/, Artic- differences between tongue contours of vowels with ulation, Pharyngealization and without following /r/. The research questions are: (1) How does the tongue configuration differ in 1. INTRODUCTION word pairs with and without /r/? (2) What is the tem- poral extent of the coarticulatory influence of /r/? The reduction of consonantal /r/ in coda position to a pharyngealized vowel is described as a dis- 2. MATERIALS AND METHODS tinct and salient feature of east central German va- rieties [6, 14, 23] but also in south western vari- 2.1. Data collection eties such as Swabian [12]. As Khan [14] shows for Upper Saxon, /r/ surfaces in this position as pha- Seven male speakers aged between 26 and 28 from ryngealization of the preceeding vowel and also on the south of Saxony-Anhalt were recorded. They all adjacent consonantal material. Due to the temporal belong to the same circle of friends, along with the overlap this results in more monophthongal pharyn- first author, which, as far as possible, ensured an in- geal qualities in combination with short vowels (e.g. formal situation during recording. Q [SpO: t] Sport ‘sport’) [22]. Ultrasound data of the mid-sagittal contour of The dark or ‘muffled’ quality of pharyngealized the tonge was captured using a transducer type segments is the acoustic consequence of the articula- 35C20EA attached to a Mindray DP2200 Ultra- tory configuration of the vocal tract. The narrowing sound system. The transducer frequency was in the pharyngeal passage is either produced by con- 2,5 MHz with a depth setting of 12.9 cm, an internal tracting the constrictor muscles or by retracting the frame rate of 58 fps and a field of view of 90◦. Af- tongue root [16]. The enlargement of the oral cavity ter de-interlacing the video frame rate was approxi- results in a lowered F2 while the smaller pharyngeal mately 60 fps [28]. The acoustic signal was recorded cavity results in a raised F1 [24]. Similar patterns using a condenser microphone (AKG C1000S) and of /r/ have been described for Scottish English using processed with Articulate Assistant Advanced soft- Ultrasound Tongue Imaging (UTI) [18, 17]. They ware (AAA, [5]) along with the video signal. Accu- show vowel retraction and pharyngealization in de- rate synchronization of the video and the audio sig- rhoticized variants. nal was achieved using a synchronization impulse While pharyngealization has been studied exten- produced by the SyncBrightUp unit [4]. An accu- rate estimate of the video frame rate of the ultra- points by superimposing a fan grid consisting of 42 sound machine was calculated in order to match the radial axes on each frame. The fitting process was audio signal correctly. The ultrasound probe was done semi-automatically using an edge-detection al- kept in a relatively stable position using a purpose- gorithm implemented in the AAA software which built headset (for details see [21]), however, no addi- allowed for manual correction of the splines where tional video signal or bite plane was captured to ver- the algorithm failed or no tongue contour was visible ify that there were no movement of the probe during e.g. due to the shadow of the hyoid bone. the recording. Palate traces were recorded only once Splines were then exported to a workspace for at the beginning of the recording session whilst the analysis. An average tongue-surface spline was cre- subject swallowed mineral water [27]. ated for each word and each time point over the Data presented here is taken from seven word five repetitions. In order to quantify the differences pairs containing the short vowels /Y E a O U/ and dif- in tongue configuration of words with and without fering in the presence or absence of coda /r/. Tar- /r/ throughout the word, pairwise comparisons were gets were embedded in meaningful sentences. The made between the mean spline of the /r/ and /r/-less sentence frame for each pair of words was kept the word pairs. The distance between each pair of av- same but varied between different pairs of words, erage splines was calculated by measuring along the e.g. Sie ist nach Born/Bonn gefahren (‘She went to 42 radial axes where the two average splines inter- Born/Bonn’), Sie hat den Metz/März geliebt (‘She sected the fan line. Root mean square (RMS) dis- loved the mason/March’). The decision against a tances for each average spline pair for each time wordlist and pseudo words which would have al- point were calculated from these interspline distance lowed for better control of coarticulatory influence measures (see [18] and [25] for more details on this of surrounding consonantal material was made to method). avoid making the target the main focus of interest, The first three formant values were estimated at to enhance naturalness and to evoke more vernacu- the annotated time points during the vowel (V1, V2, lar speech. V3, V4, V5) with PRAAT [8]. For statistical ana- Stimuli were presented on a screen in a random- lysis linear mixed models (LMMs), as implemented ized order using the facility provided in AAA. Each in the lme4 package [7], were run in R [20]. To find block was repeated five times in the same order. the model with the best fit to the data, comparisons Some tokens had to be omitted because no synchro- were done in a stepwise fashion by adding more fac- nization impulse was found in the recording. tors (or interactions) in each step to the model and comparing this model with the reduced model with- 2.2. Data analysis out the particular factor (or interaction) in question. We then decided on keeping a factor/interaction de- Target words were annotated and segmented in pending on the result of the likelihood ratio test (p- PRAAT [8] and imported back into AAA for fur- value < .05). ther processing and analysis. To capture the tem- poral extent of the influence of /r/, five normalized 3. RESULTS time points in the vocalic portion of the word were annotated (beginning (V1), after 25% (V2), after 3.1. Articulatory analysis 50% (V3), after 75% (V4) and at the end of the vowel (V5)). In addition, three time points during In order to abstract away from a certain vowel cat- the following consonant or consonant cluster were egory an average spline was created for each time annotated. Since the syllable structure of the target point over all vowel categories for the /r/ and /r/-less words vary, the structural meaning of the time points words. By doing so, all coarticulatory information changes. Nevertheless, the three time points capture of different vowels, onsets and following consonants the temporal extent of the consonant. For the nasal is removed. Since the only differing aspect in these /n/, lateral /l/ and the fricative /s/ three points (25% comparisons is the presence or absence of /r/, av- (C1), 50% (C2) and 75% after the onset (C3)) were erage splines can be interpreted in terms of the im- selected. For the plosives /k t/ and the affricate /ts/ pact of /r/ on tongue configuration over several time two points during the closure (after one third and af- points throughout the word allowing comparisons of ter two thirds) and one in the middle of the release different time points over word tokens and more im- or in the middle of the following fricative were se- portantly over multiple speakers. Since the size, po- lected. sition and rotation of the probe varies for different Splines were fitted to the visible surface of the speakers, splines are normally not directly compara- tongue in the eight frames closest to these eight time ble over multiple speakers. Figure 1: Average tongue splines for /r/ (dark grey) and /r/-less (light grey) vowels for all eight time points for subject RR with standard deviation indicated by the dotted lines. Palate trace is indicated in red and significant interspline distances between the two splines (two-tailed t-test, p < .05) are shown by the thicker spokes on 42 fan lines.