Working papers / Lund University, Department of Linguistics and Phonetics
Working Papers in Linguistics began in 1969 as an output for reports on research in progress. It contains principally work from researchers at the Department of Linguistics and Phonetics at Lund University.
Department of Linguistics and Phonetics, Lund University
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‘superassp' and the need for a sparse signal track data format
The digital processing of phonetic data has long been based on the same basic data structures and consequently been stored in essentially the same manner. The transition to structured database-based workflows and the development of more complex analyses challenge the established data structures and storage models. I propose a sparsely defined data track model for structured storing of locally define signal information and suggest an implementation. The use of sparse data created by the amalgamating signal processing library 'superassp' is discussed within a speech database management system.
Dating the new open TRAP sound change in South East England
The new open trap sound change was reported in the 1980s, in Received Pronunciation. The earliest example found by Fabricius in 2007 was born in 1926, still Received Pronunciation. Jones and Gimson reported only the earlier closer trap. The earliest regional example of new open trap, born in 1866 in Kent, was reported by Wood in 2017. Four groups of informants were studied, RP and regional. The earliest RP speaker found with new open trap was born in 1857, one hundred years before it was noticed. This raises questions like how did Jones manage to miss it? (or ignore it?). Suggested explanations include inadequate vowel theory (the Bell vowel model) and experimental methods (feeling the Bell vowel locations).
Segmental durations as a correlate of Swedish word accents
This study aims to scrutinize the role of segmental duration as a correlate of the two Swedish word accents, asking whether it is a robust correlate, independent of tonal complexity and phrase-level prosodic factors. To this end, we examined segmental durations of Accent 1 and Accent 2 words in two regional dialects, controlling for focus and phrase finality. Recordings from 24 speakers were analysed. The results showed that the vowel in the stressed syllable and the post-vocalic consonant were produced longer with Accent 2 than with Accent 1, irrespective of the speakers' dialect, focus condition and position in the utterance.
Perceiving head movements in news readings
Previous research has shown that visual information can be integrated in the perception of prominence, but the available evidence stems mostly from controlled experimental settings, often making use of synthetic stimuli. The present study provides evidence from spontaneously produced head gestures that occurred in Swedish television news readings. Materials were rated for word prominence by 85 adult volunteers in a between-subjects design (audio-visual vs. audio-only ratings) using a crowd-sourcing approach. Accented words accompanied by a head movement were perceived as more prominent than accented words lacking a head movement. Crucially, the difference in perceived prominence level between words with and without a head gesture was found to be larger in an audio-visual rating condition compared to an audio-only condition. The results suggest that visual prominence signals are integrated in speech processing even in a relatively uncontrolled, naturalistic setting, such as watching the news.
Given the importance of the entire voice source in prominence expression, this paper aims to explore whether the word accent distinction can be defined by the voice quality dynamics moving beyond the tonal movements. To this end, a list of word accent pairs in Central Swedish were recorded and analysed based on a set of acoustic features extracted from the accelerometer signal. The results indicate that the tonal movements are indeed accompanied by the voice quality dynamics such as intensity, periodicity, harmonic richness and spectral tilt, and suggest that these parameters might contribute to the perception of one vs. two peaks associated with the word accent distinction in this regional variant of Swedish. These results, although based on limited data, are of crucial importance for the designation of voice quality variation as a prosodic feature per se.
Phonemic and subphonemic cues in prediction
The brain is constantly trying to predict the future and phonological and prosodic cues are used to anticipate forthcoming information. Even cues on the subphonemic level such as vowel transitions, nasalisation and assimilation across word boundaries are useful in anticipating upcoming speech. In event-related potential (ERP) studies examining subphonemic and lexical/phonological mismatches, only the latter yielded N400 effects, an ERP component associated with lexical prediction error. The results indicate that phonetic cues are resolved prelexically. However, subphonemic cues still seem to be used in prediction as evidenced by valid cues yielding faster fixations in eye-tracking studies and invalid cues modulating P600 amplitudes, indicating structural violations and context updating.
Swedish has been generally assumed not to have any well-defined question intona­tion. However, with respect to Southern Swedish, Lindblad & Gårding (1973) present data showing final rises in polar (Y/N) questions. Gårding (1979) also as­sumes a broader and higher F0 range in Y/N questions than in statements, particu­larly on the final focussed word. The present study investigates the extent to which these question cues occur in a material involving spontaneous dialogues led by a speaker of Southern Swedish (Malmö). Results for utterances with question syntax show final rises in 16% of the Y/N questions and 3% of the Wh-questions. For utterances without question syntax, 79% were associated with final rises. Compar­ing F0 on the first prosodic word of questions, both Y/N- and Wh-questions showed a significantly higher F0 level (ca. 2-3 ST higher) than statements. A further com­parison of the F0 level on the most prominent word following the first prosodic word in questions and statements showed that Y/N questions had a higher F0 on the most prominent word than statements. However, Wh-questions did not differ significantly from statements in that respect. Thus initial F0-level appears to be a strong prosodic cue distinguishing between questions (both Y/N questions and Wh-questions) and statements in the Southern Swedish material examined. F0 level on the most promi­nent word following the first prosodic word is also a reliable prosodic cue distinguishing Y/N questions from statements and Wh-questions, but not for distinguishing between Y/N questions and Wh-questions.
Stress manipulation in text-to-speech synthesis using speaking rate categories
The challenge of controlling prosody in text-to-speech systems (TTS) is as old as TTS itself. The problem is not just to know what the desired stress or intonation patterns are, nor is it limited to knowing how to control specific speech parameters (e.g. durations, amplitude, fundamental frequency). We also need to know the precise speech parameter settings that correspond to a certain stress or intonation pattern – over entire utterances. We propose that the powerful TTS models afforded by deep neural networks, combined with the fact that speech parameters often are correlated and vary in orchestration, allows us to solve at least some stress and intonation parts using simplified control over relatively easy-to-control parameters, rather than detailed control over many parameters. The paper presents a straightforward method of guiding word durations without recording training material especially for this purpose. The resulting TTS engine is used to produce sentences containing Swedish words that are unstressed in their most common function, but stressed in another common function. The sentences are designed so that it is clear to a listener that the second function is the intended. In these cases, TTS engines often fail and produce an unstressed version. A group of 20 listeners compared samples that the TTS produced without guidance with samples where it was instructed to slow down the test words. The listeners almost unanimously preferred the latter version. This supports the notion that due to the orchestrated variation of speech characteristics and the strength of modern DNN models, we can provide prosodic guidance to DNN-based TTS systems without having to control every characteristic in detail.
Differences in acoustically determined sentence stress between native and L2 speakers of Finland Swedish
This study describes a pilot attempt to use acoustically determined sentence stress in distinguishing native and L2 speakers of Finland Swedish at different proficiency levels. The study is part of the DigiTala project that examines and develops automatic tools for spoken L2 assessment. Stressed syllables were detected in 235 L2 and 30 L1 speech samples using combinations of f0, intensity, and duration. Differences were found in the relative number of stressed syllables between native and L2 speakers using f0 and duration or all three features. Further research with more consistent speech data is needed to establish reliable automatic measures of sentence stress.
The perceptual importance of falling pitch for speakers from different dialects of Swedish
Falling pitch has long been argued to be a key feature in the distinction of Swedish pitch accents. In this paper, neurophysiological evidence substantiating the perceptual importance of HL pitch contours at the word level is discussed. When presented with novel words, Swedes across different dialect areas preattentively distinguished meaningful words with falling pitch. The preattentive response to meaningful HL contours in foreign words was likely based on transfer from the native tongue, thus providing evidence for the importance of falling pitch in the discrimination of word accents in four Swedish dialect areas. However, while falls appear to hold a key function in all dialect groups, additional dialect-dependent pitch patterns emerged that also affected preattentive word discrimination.
Primary auditory cortex’s vowel representation
Sound frequencies are represented in the primary auditory cortex (PAC) in a tonotopic structure which can be measured using functional magnetic resonance imaging (fMRI). A previous study has investigated vowels [ɑ] and [i] and seen a correlation between the vowels’ activation and the activation of simple tones corresponding to the vowels’ formant frequencies. Other vowels have not yet been studied. In this study, we are investigating [ɑ],[ɛ], [i], and [u] and compared those with activation of simple tones corresponding to their formant frequencies. This is ongoing work, and only five volunteers have participated. The preliminary results vary from high correlation between areas activated to low or no correlation. More data has to be collected to draw any further conclusions.