Open Access

The goal of this study was to evaluate invariance vs. variability in both articulation and acoustics of speech production units. To keep interaction of controlled variables manageable, only a very simple subrange of speech productions was studied. Three different vowel qualities and six different consonants were examined in a VCV sequence embedded in an utterance. Beside coarticulation vocal effort was a further factor of perturbation occuring in natural speech. The set of consonants comprised various modes of articulation (stop, fricative, nasal, lateral) all produced at virtually the same place of articulation, viz. (post-) alveolar. The range of vowel environments /i:/, /e:/, /a:/ was selected for differences in height, in order to vary coarticulatory effects between the segments. Utterances were produced at two different volume levels, viz. normal and loud speech. Experiments by others have demonstrated that higher speech volume is not simply realized as a raised sound pressure level or as raised intensity. For loud speech a number of different correlates were observed, as raised subglottal pressure (see Ladefoged/McKinney 1963), raised fundamental frequency, raised first formant, and change of segmental durations (e.g. Traunmüller/Eriksson 2000). Furthermore an effect on jaw height was observed in vowels, which is that in vowel production in loud speech the jaw has a lower position. In earlier studies results have been presented for either articulatory (Schulman 1989) or acoustic changes (Traunmüller/Eriksson 2000) associated with higher volume. The present study examines effects of higher volume level on vowels as well as on consonants, in the articulatory as well as the acoustic channel. Data from six German speakers (5 male, 1 female) were recorded and analyzed. In the 266 articulatory channel jaw and tongue-tip movements were analyzed, in the acoustic domain segmental characteristics as formants, duration, intensity and fundamental frequency. The main results can be described as follows: - Jaw height in vowels depends on vowel height, in the vowel production of loud speech the jaw is lowered significantly. - Jaw height in consonants depends on the type of consonant (very high for /s/, / /, /t/, fairly low for /n/, /l/). Speaking at higher volume level does not have a significant effect on jaw height during (post-) alveoloar consonant production, coarticulatory effect of vowel context is mainly found with /n/ and /l/. - In loud speech jaw gestures have higher amplitude. - Acoustic segmental duration is changed: Vowels are lengthened and consonants are shortened. - Fundamental frequency in vowel segments is raised significantly. - In all vowels the first formant is raised. - The second formant of the non-front vowel /a:/ is raised. This work has demonstrated that jaw articulation in a number of alveolar consonants is remarkably precise and that motor equivalence only plays a minor role. Moreover, it has been shown that in the face of the generally larger variability of acoustic and articulatory parameters, the results are best considered in terms of perceptual invariants. The findings also substantiate the complexity of articulatory and acoustic reorganisation in loud speech.

In Articulatory Phonology the jaw is not controlled individually but serves as an additional articulator to achieve the primary constriction. In this study the timing of jaw and tongue tip gestures for the coronal consonants /s, , t, d, n, l/ is analysed by means of EMMA. The findings suggest that the tasks of the jaw for the fricatives are to provide a second noise source and to stabilise the tongue position (more pronounced for /s/). For the voiceless stop, the speakers seem to aim at a high jaw position for producing a prominent burst. For /l/ a low jaw position is essential for avoiding lateral contact and for the apical articulation of this sound.

It is well-accepted that the jaw plays an active role in influencing vowel height. The general aim of the current study is to further investigate the extent to which the jaw is active in producing consonantal distinctions, with specific focus on coronal consonants. Therefore, tongue tip and jaw positions are compared for the German coronal consonants Is, J, t, d, n, 1/, that is, consonants having the same active articulators (apical/laminal) but differing in manner of articulation. In order to test the stability of articulatory positions for each of these coronal consonants, a natural perturbation paradigm was introduced by recording two levels of vocal effort: comfortable, and loud without shouting. Tongue and jaw movements of five speakers of German were recorded by means of EMMA during /aCa/ sequences. By analyzing the tongue tip and jaw positions and their spatial variability we found that (1) the jaw's contribution to these consonants varies with manner of articulation, and (2) for all coronal consonants the positions are stable across loudness conditions except for those of the nasal. Results are discussed with respect to the tasks of the jaw, and the possible articulatory adjustments that may accompany louder speech.

The vowel quality in some diphthongs of Swabian (an upper german dialect) was determined by measurement of first and second formant values. A minimal contrast could be shown between two different diphthong qualities […], where for Standard German only one is assumed, viz. /ai/. The two diphthong qualities differ only slightly in onset and offset vowel quality, so a better understanding of their relationship was expected from an examination of their dynamic aspects. Our preliminary results suggest that there is indeed a difference in the temporal structure of the two diphthongs.

The aim of this paper is to highlight the actual need for corpora that have been annotated based on acoustic information. The acoustic information should be coded in features or properties and is needed to inform further processing systems, i.e. to present a basis for a speech recognition system using linguistic information. Feature annotation of existing corpora in combination with segmental annotation can provide a powerful training material for speech recognition systems, but will as well challenge the further processing of features to segments and syllables. We present here the theoretical preliminaries for our multilingual feature extraction system, that we are currently working on.