Reduktion in natürlicher Sprache

Natural (conversational) speech, compared to cannonical speech, is earmarked by the tremendous amount of variation that often leads to a massive change in pronunciation. Despite many attempts to explain and theorize the variability in conversational speech, its unique characteristics have not played a significant role in linguistic modeling. One of the reasons for variation in natural speech lies in a tendency of speakers to reduce speech, which may drastically alter the phonetic shape of words. Despite the massive loss of information due to reduction, listeners are often able to understand conversational speech even in the presence of background noise. This dissertation investigates two reduction processes, namely regressive place assimilation across word boundaries, and massive reduction and provides novel data from the analyses of speech corpora combined with experimental results from perception studies to reach a better understanding of how humans handle natural speech. The successes and failures of two models dealing with data from natural speech are presented: The FUL-model (Featurally Underspecified Lexicon, Lahiri & Reetz, 2002), and X-MOD (an episodic model, Johnson, 1997). Based on different assumptions, both models make different predictions for the two types of reduction processes under investigation. This dissertation explores the nature and dynamics of these processes in speech production and discusses its consequences for speech perception. More specifically, data from analyses of running speech are presented investigating the amount of reduction that occurs in naturally spoken German. Concerning production, the corpus analysis of regressive place assimilation reveals that it is not an obligatory process. At the same time, there emerges a clear asymmetry: With only very few exceptions, only [coronal] segments undergo assimilation, [labial] and [dorsal] segments usually do not. Furthermore, there seem to be cases of complete neutralization where the underlying Place of Articulation feature has undergone complete assimilation to the Place of Articulation feature of the upcoming segment. Phonetic analyses further underpin these findings. Concerning deletions and massive reductions, the results clearly indicate that phonological rules in the classical generative tradition are not able to explain the reduction patterns attested in conversational speech. Overall, the analyses of deletion and massive reduction in natural speech did not exhibit clear-cut patterns. For a more in-depth examination of reduction factors, the case of final /t/ deletion is examined by means of a new corpus constructed for this purpose. The analysis of this corpus indicates that although phonological context plays an important role on the deletion of segments (i.e. /t/), this arises in the form of tendencies, not absolute conditions. This is true for other deletion processes, too. Concerning speech perception, a crucial part for both models under investigation (X-MOD and FUL) is how listeners handle reduced speech. Five experiments investigate the way reduced speech is perceived by human listeners. Results from two experiments show that regressive place assimilations can be treated as instances of complete neutralizations by German listeners. Concerning massively reduced words, the outcome of transcription and priming experiments suggest that such words are not acceptable candidates of the intended lexical items for listeners in the absence of their proper phrasal context. Overall, the abstractionist FUL-model is found to be superior in explaining the data. While at first sight, X-MOD deals with the production data more readily, FUL provides a better fit for the perception results. Another important finding concerns the role of phonology and phonetics in general. The results presented in this dissertation make a strong case for models, such as FUL, where phonology and phonetics operate at different levels of the mental lexicon, rather than being integrated into one. The findings suggest that phonetic variation is not part of the representation in the mental lexicon.Natürliche (spontane) Sprache in Dialogen zeichnet sich, im Vergleich zu kanonischer Sprache, vor allem durch das enorme Ausmaß an Variation aus. Diese kann oft dazu führen, dass Wörter in der Aussprache massiv verändert werden. Trotz einiger Bemühungen, Variabilität in natürlicher Sprache zu erklären und theoretisch zu fassen, haben die einzigartigen Merkmale natürlicher Sprache kaum Eingang in linguistische Modelle gefunden. Einer der Gründe, warum Variation in natürlicher Sprache zu beobachten ist, liegt in der Tendenz der Sprecher, Sprache zu reduzieren. Dies kann die phonetische Gestalt von Wörtern drastisch beeinflussen. Obwohl hierdurch massiv Information durch Reduktion verloren geht, sind Hörer oft in der Lage Spontansprache zu verstehen, sogar, wenn Hintergrundgeräusche dies erschweren. Diese Dissertation untersucht zwei Reduktionsprozesse: Regressive Assimilation des Artikulationsortes über Wortgrenzen hinweg und Massive Reduktion. Es werden neue Daten präsentiert, die durch die Analysen von Sprachkorpora gewonnen wurden. Außerdem stehen experimentelle Ergebnisse von Perzeptionsstudien im Mittelpunkt, die helfen sollen, besser zu verstehen, wie Menschen mit natürlicher Sprache umgehen. Die Dissertation zeigt die Erfolge und Probleme von zwei Modellen im Umgang mit Daten von natürlicher Sprache auf: Das FUL-Modell (Featurally Underspecified Lexicon , Lahiri & Reetz, 2002), und X-MOD (ein episodisches Modell, Johnson, 1997). Aufgrund unterschiedlicher Annahmen machen die zwei Modelle verschiedene Vorhersagen für die beiden Reduktionsprozesse, die in dieser Dissertation untersucht werden. Es werden Art und Auswirkungen der beiden Prozesse für Sprachproduktion untersucht und die Konsequenzen für das Sprachverstehen beleuchtet. Was die Sprachproduktion betrifft, so zeigt eine Korpusanalyse von natürlich gesprochenem Deutsch, dass der Reduktionsprozess regressive Assimilation des Artikulationsortes nicht obligatorisch statt findet. Gleichzeitig wird eine hervorstechende Asymmetrie deutlich: Abgesehen von einigen wenigen Ausnahmen werden ausschließlich [koronale] Segmente assimiliert, [labiale] und [dorsale] Segmente normalerweise nicht. Außerdem, so legen die Produktionsdaten nahe, gibt es Fälle, in denen die Assimilation des Artikulationsortes an den Artikulationsort des Folgesegmentes komplett ist, also eine vollständige Neutralisierung der Merkmalskontraste vom Sprecher vorgenommen wurde. Phonetische Analysen bestätigen dieses Resultat. Im Fall von Löschungen und massiven Reduktion demonstrieren die Ergebnisse eindeutig, dass phonologische Regeln – im klassischen generativen Sinne – nicht in der Lage sind, die Reduktionsmuster zu beschreiben, die in Spontansprache vorkommen. Alles in allem zeigen die Analysen von massiven Reduktionen und Löschungen keine eindeutigen Muster auf. Um einzelne Faktoren, die Reduktionen beeinflussen, genauer untersuchen zu können, wurde die Löschung von (Wort) finalem /t/ anhand eines neuen, für diesen Zweck kreierten Korpus durchgeführt. Die Analyse dieses Korpus unterstreicht, dass, obwohl phonologischer Kontext eine gewichtigen Einfluss darauf hat, ob Segmente (d.h. /t/) gelöscht werden, dieser Einfluss eher als Tendenz verstanden werden muss, nicht als absolute Bedingung. Dieses Resultat trifft auch auf andere Löschungsprozesse zu. Beide Modelle (X-MOD und FUL), die in dieser Dissertation untersucht werden, gehen im Kern der Frage nach, wie Hörer Sprache verstehen. Fünf Experimente untersuchen, wie reduzierte Sprache von menschlichen Hörern wahrgenommen wird. Ergebnisse von zwei Studien zeigen, dass Assimilationen von deutschen Hörern durchaus als komplett neutralisiert wahrgenommen werden. Was die Perzeption von massiv reduzierten Wörtern betrifft, belegen die Resultate von Transkriptionsstudien und Priming-Experimenten, dass solche Wörter nicht als Wortkandidaten für die korrekten lexikalischen Einträge akzeptiert werden, wenn sie ohne ihren Satz-Kontext dargeboten werden. Insgesamt ist das abstraktionistische FUL-Modell besser in der Lage, die Daten zu erklären, die in dieser Dissertation präsentiert werden. Auf den ersten Blick scheint X-MOD zwar etwas besser geeignet, die Produktionsdaten zu erklären, hauptsächlich jedoch, weil Variation als Grundannahme im Modell verankert ist. FUL ist klar überlegen, was die Perzeptionsseite betrifft. Ein weiteres wichtiges Ergebnis dieser Dissertation ist die Rolle, die Phonologie und Phonetik im Allgemeinen zugedacht werden kann. Die Resultate, die hier vorgestellt werden, liefern starke Argumente für Modelle – wie z.B. FUL – in denen Phonologie und Phonetik auf verschiedenen Ebenen des mentalen Lexikons aktiv sind und nicht in einem integriert sind. Die Befunde legen nahe, dass phonetische Variation nicht Teil der Repräsentation im mentalen Lexikon ist

The Perceptual Effect of L1 Prosody Transplantation on L2 Speech: The Case of French Accented German

Research has shown that language learners are not only challenged by segmental differences between their native language (L1) and the second language (L2). They also have problems with the correct production of suprasegmental structures, like phone/syllable duration and the realization of pitch. These difficulties often lead to a perceptible foreign accent. This study investigates the influence of prosody transplantation on foreign accent ratings. Syllable duration and pitch contour were transferred from utterances of a male and female German native speaker to utterances of ten French native speakers speaking German. Acoustic measurements show that French learners spoke with a significantly lower speaking rate. As expected, results of a perception experiment judging the accentedness of 1) German native utterances, 2) unmanipulated and 3) manipulated utterances of French learners of German suggest that the transplantation of the prosodic features syllable duration and pitch leads to a decrease in accentedness rating. These findings confirm results found in similar studies investigating prosody transplantation with different L1 and L2 and provide a beneficial technique for (computer-assisted) pronunciation training

Intradural spinal metastasis of renal cell cancer. Report of a case and review of 26 published cases

Metastatic disease in the intradural compartment of the spine is a rare manifestation of cancer. We report the case of an 82-year-old patient with an intradural, extramedullary metastasis of renal cell carcinoma in the cervical spine. A literature search for intradural spinal metastases of renal cell carcinoma yielded a total of 26 further cases. 18 patients had sporadic renal cell carcinoma, and 9 patients had von Hippel-Lindau disease (VHL) in which the metastases of the renal cell carcinoma were embedded within spinal haemangioblastomas. Patients presented with paresis, back pain, altered sensation or, less frequently, bladder dysfunction. Intradural spinal metastases were diagnosed at an earlier age in VHL patients than in sporadic cases (mean 43 ± 5years vs. 60 ± 14.5years). The metastasis was surgically removed in 81% of patients. Pain improved in all patients, paresis in 90%, hypaesthesia in 38% and bladder dysfunction in 50%. Death occured as a result of systemic cancer progression. 93% of patients in the sporadic renal cell cancer group died within 1.5years, whereas two thirds of the VHL patients were alive after 2year

Effect of neoadjuvant chemoradiation and postoperative radiotherapy on expression of heat shock protein 70 (HSP70) in head and neck vessels

<p>Abstract</p> <p>Background</p> <p>Preoperative radiotherapy and chemotherapy in patients with head and neck cancer result in changes to the vessels that are used to construct microsurgical anastomoses. The aim of the study was to investigate quantitative changes and HSP70 expression of irradiated neck recipient vessels and transplant vessels used for microsurgical anastomoses.</p> <p>Methods</p> <p>Of 20 patients included in this study five patients received neoadjuvant chemoradiation, another five received conventional radiotherapy and 10 patients where treated without previous radiotherapy. During surgical procedure, vessel specimens where obtained by the surgeon. Immunhistochemical staining of HSP70 was performed and quantitative measurement and evaluation of HSP70 was carried out.</p> <p>Results</p> <p>Conventional radiation and neoadjuvant chemoradiation revealed in a thickening of the intima layer of recipient vessels. A increased expression of HSP70 could be detected in the media layer of the recipient veins as well as in the transplant veins of patients treated with neoadjuvant chemoradiation. Radiation and chemoradiation decreased the HSP70 expression of the intima layer in recipient arteries. Conventional radiation led to a decrease of HSP70 expression in the media layer of recipient arteries.</p> <p>Conclusion</p> <p>Our results showed that anticancer drugs can lead to a thickening of the intima layer of transplant and recipient veins and also increase the HSP70 expression in the media layer of the recipient vessels. In contrast, conventional radiation decreased the HSP70 expression in the intima layer of arteries and the media layer of recipient arteries and veins. Comparing these results with wall thickness, it was concluded, that high levels of HSP70 may prevent the intima layer of arteries and the media layer of vein from thickening.</p

Methods of investigating vowel interferences of French learners of German

International audienceThe French and German vowel inventories [Fougeron & Fougeron, 1999, Kohler, 1999] show many similarities, for instance, both have a series of front rounded vowels. Contrary to German, French has no vowel length contrast. Although specialized teaching materials for German consider the problem of vowel length/tenseness (e.g. [Hirschfeld, 2014; Hirschfeld et al., 2007]), it is still unclear how frequently vowel errors occur in L2 speech and which pairs of long-tense and short-lax vowels create the most serious difficulties for French learners of German. We present three methods to analyze the interference processes occurring in read speech of French learners of German (60 sentences, 50 subjects). First, we analyzed phone confusion matrices based on hand-labeled data. The most frequent confusions appear for two long-tense/short-lax distinctions. Second, in a perception study, German native speakers listened to words belonging to minimal pairs like Miete - Mitte ('rent-middle') differing in length/tenseness. Results indicate that, overall, short vowels were identified correctly less often (64\%) than long vowels (77\%), but with great inter-individual differences. Although most problems occur in the beginner group, every second advanced learner shows for short vowels an identification rate lower than chance, which means they were perceived as long by German native listeners.Finally, acoustic measurements of the minimal pair words revealed very different strategies: some speakers show a general tendency to lengthen and other speakers to shorten vowels.The results of these three investigations help to create a more detailed account of the transfer of vowel contrasts, extending prior research on vowel perception [Kingston, 2003; Flege & MacKay, 2004], with orthography as a possible source of interference. Furthermore, the results of the studies can be used to create individualized training and feedback for foreign language learners

Methods of investigating vowel interferences of French learners of German

International audienceThe French and German vowel inventories [Fougeron & Fougeron, 1999, Kohler, 1999] show many similarities, for instance, both have a series of front rounded vowels. Contrary to German, French has no vowel length contrast. Although specialized teaching materials for German consider the problem of vowel length/tenseness (e.g. [Hirschfeld, 2014; Hirschfeld et al., 2007]), it is still unclear how frequently vowel errors occur in L2 speech and which pairs of long-tense and short-lax vowels create the most serious difficulties for French learners of German. We present three methods to analyze the interference processes occurring in read speech of French learners of German (60 sentences, 50 subjects). First, we analyzed phone confusion matrices based on hand-labeled data. The most frequent confusions appear for two long-tense/short-lax distinctions. Second, in a perception study, German native speakers listened to words belonging to minimal pairs like Miete - Mitte ('rent-middle') differing in length/tenseness. Results indicate that, overall, short vowels were identified correctly less often (64\%) than long vowels (77\%), but with great inter-individual differences. Although most problems occur in the beginner group, every second advanced learner shows for short vowels an identification rate lower than chance, which means they were perceived as long by German native listeners.Finally, acoustic measurements of the minimal pair words revealed very different strategies: some speakers show a general tendency to lengthen and other speakers to shorten vowels.The results of these three investigations help to create a more detailed account of the transfer of vowel contrasts, extending prior research on vowel perception [Kingston, 2003; Flege & MacKay, 2004], with orthography as a possible source of interference. Furthermore, the results of the studies can be used to create individualized training and feedback for foreign language learners

Influence of L1 prominence on L2 production: French and German speakers

International audienceFrench and German differ with respect to the representation and implementation of prominence. French can be assumed to have no prominence represented in the mental lexicon and accents are regularly assigned post-lexically on the last full vowel of an accentual group. In German, prominence is considered to be represented lexically. This difference may give rise to interferences when German speakers learn French and French speakers learn German. Results of a judgment task (conducted with 3 trained phoneticians) of native and non-native productions of French learners of German and German learners of French, all of them beginners, show that both groups have not completely acquired the correct suprasegmental structures in the respective L2, since both groups are worse concerning the correct placement of prominence than the native speakers. Furthermore, the results suggest that the native pattern is one of the most important factors for wrong prominence placements in the foreign language, e.g., if the prominence placement of L1 and L2 coincide, speakers produce the smallest amount of errors. Finally, results indicate that visual display of accented syllables increases the likelihood of correct accent placement significantly

Bioinspired Polydopamine Coating as an Adhesion Enhancer Between Paraffin Microcapsules and an Epoxy Matrix

Microencapsulated phase change materials (PCMs) are attracting increasing attention as functional fillers in polymer matrices, to produce smart thermoregulating composites for applications in thermal energy storage (TES) and thermal management. In a polymer composite, the filler–matrix interfacial adhesion plays a fundamental role in the thermomechanical properties. Hence, this work aims to modify the surface of commercial PCM microcapsules through the formation of a layer of polydopamine (PDA), a bioinspired polymer that is emerging as a powerful tool to functionalize chemically inert surfaces due to its versatility and great adhesive potential in many different materials. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) evidenced that after PDA coating, the surface roughness increased from 9 to 86 nm, which is beneficial, as it allows a further increase in the interfacial interaction by mechanical interlocking. Spectroscopic techniques allowed investigating the surface chemistry and identifying reactive functional groups of the PDA layer and highlighted that, unlike the uncoated microcapsules, the PDA layer is able to react with oxirane groups, thereby forming a covalent bond with the epoxy matrix. Hot-stage optical microscopy and differential scanning calorimetry (DSC) highlighted that the PDA modification does not hinder the melting/crystallization process of the paraffinic core. Finally, SEM micrographs of the cryofracture surface of epoxy composites containing neat or PDA-modified microcapsules clearly evidenced improved adhesion between the capsule shell and the epoxy matrix. These results showed that PDA is a suitable coating material with considerable potential for increasing the interfacial adhesion between an epoxy matrix and polymer microcapsules with low surface reactivity. This is remarkably important not only for this specific application but also for other classes of composite materials. Future studies will investigate how the deposition parameters affect the morphology, roughness, and thickness of the PDA layer and how the layer properties influence the capsule–matrix adhesion

Bio-inspired deposition of electrochemically exfoliated graphene layers for electrical resistance heating applications

Electrochemically exfoliated graphene (eeG)layers possess a variety of potential applications, e.g. as susceptor material for contactless induction heating in dynamic electro-magnetic fields, and as flexible and transparent electrode or resistivity heating elements. Spray coating of eeG dispersions was investigated in detail as a simple and fast method to deposit both, thin conducting layers and ring structures on polycarbonate substrates. The spray coating process was examined by systematic variation of dispersion concentration and volume applied to heated substrates. Properties of the obtained layers were characterized by UV-VIS spectroscopy, SEM and Confocal Scanning Microscopy. Electrical conductivity of eeG ring structures was measured using micro-four-point measurements. Modification of eeG with poly(dopamine) and post-thermal treatment yields in the reduction of the oxidized graphene proportion, an increase in electrical conductivity, and mechanical stabilization of the deposited thin layers. The chemical composition of modified eeG layer was analyzed via x-ray photoelectron spectroscopy pointing to the reductive behavior of poly(dopamine). Application oriented experiments demonstrate the direct electric current heating (Joule-Heating) effect of spray-coated eeG layers.This research work was funded by the Federal Ministry of Education and Research (BMBF) project no. 01DS19024

Analysis of phone confusion matrices in a manually annotated French-German learner corpus

International audienceThis paper presents an analysis of the non-native and native pronunciations observed in a phonetically annotated bilingual French-German corpus. After a forced-choice automatic annotation a large part of the corpus was checked and corrected manually on the phone level which allows a detailed comparison of the realized sounds with the expected sounds. The analysis is reported in terms of phone confusion matrices for selected error-prone classes of sounds. It revealed that German learners of French have most problems with obstruents in word-final position whereas French learners of German show complex interferences with the vowel contrasts for length and quality. Finally, the correct pronunciation rate of the sounds, for several phonetic classes, is analyzed with respect to the learner's level, and compared to native pronunciations. One outcome is that different sound classes show different correct rates over the proficiency levels. For the German data the frequently occurring syllabic [=n] is a prime indicator of the proficiency level