Szinkronizált beszéd- és nyelvultrahang-felvételek a SonoSpeech rendszerrel

Kivonat: A jelen ismertetés az MTA–ELTE Lingvális Artikuláció Kutatócsoport ultrahangos vizsgálatainak technikai hátterét, az alkalmazott hardver- és szoftverkörnyezetet, illetőleg a folyó és tervezett kutatásokat mutatja be. A magyar és nemzetközi szakirodalmi előzmények tárgyalása után ismerteti az ultrahangnak mint az artikuláció vizsgálatában alkalmazott eszköznek a sajátosságait, összevetve más kísérleti eszközökkel és módszertanokkal. Kitér a kutatási nehézségekre is, mint például az ultrahangkép beszélőfüggő minősége, a nyelvkontúr manuális és automatikus meghatározása, végül bemutatja a kutatócsoport főbb céljait és terveit, mind az alap-, mind pedig az alkalmazott kutatások területén

A nyelvkontúr automatikus követése ultrahangos felvételeken

In recent decades, several types of devices have been constructed to track the invisible movement of the tongue. One of these is ultrasound imaging. The advantage of the measurement method is that it is suitable to track rapid movements, as well, image and sound can be synchronized, and it only causes the speaker, who is not affected by harmful radiation, minimal inconvenience. Its disadvantage is that it does not provide a full three-dimensional image but only shows a longitudinal or transverse section and the tip of the tongue cannot be seen. The longitudinal (midsagittal) section was used to track tongue movements. The automatic assessment of ultrasound pictures is a key issue as the number of frames amounts to several undred thousand so it is impossible to process them manually. The difficulty of tracking tongue contour lies in the fact that the images have a noisy background and the contour line is discontinuous. An algorithm based on dynamic programming was elaborated to track the movement of the back of the tongue. With an extreme size edge enhancing kernel and averaging construction, the process simultaneously handles the problems of break of continuity and noise. In the image obtained after smoothing, the lightest line is searched for from the left to the right edge of the image. The points of the curve thus obtained follow the uneven line of the tongue contour. To smooth the curve, screening based on discrete cosine transformation was applied

Phonological and phonetic properties of nasal substitution in Sasak and Javanese

Austronesian languages such as Sasak and Javanese have a pattern of morphological nasal substitution, where nasals alternate with homorganic oral obstruents—except that [s] is described as alternating with [ɲ], not with [n]. This appears to be an abstract morphophonological relation between [s] and [ɲ] where other parts of the paradigm have a concrete homorganic relation. Articulatory ultrasound data were collected of productions of [t, n, ʨ, ɲ], along with [s] and its nasal counterpart from two languages, from 10 Sasak and 8 Javanese speakers. Comparisons of lingual contours using a root mean square analysis were evaluated with linear mixed-effects regression models, a method that proves reliable for testing questions of phonological neutralization. In both languages, [t, n, s] exhibit a high degree of articulatory similarity, whereas postalveolar [ʨ] and its nasal counterpart [ɲ] exhibited less similarity. The nasal counterpart of [s] was identical in articulation to [ɲ]. This indicates an abstract, rather than concrete, relationship between [s] and its morphophonological nasal counterpart, with the two sounds not sharing articulatory place in either Sasak or Javanese.published_or_final_versio