The focus of this study was to explore how prosodic position and word type affect the phonetic structure and resulting perceptual identification of Korean stops and fricatives. When there is less contextual information, speakers tend to produce clearer speech. For example, consonants at the beginning of prosodic domains, such as syllables, words or phrases, are known to be more clearly articulated and distinguishable than later-occurring consonants. However, it is not yet clear whether the prosodically conditioned realizations of a segment are perceptually distinctive in continuous speech. In addition, there are few studies examining whether the properties of prosodic domain-initial segments are affected by the information content of words (real vs. nonsense words). The acoustic properties of stops and fricatives were compared across IP, PP and Wd-initial positions both in real and nonsense words. It was found that segments in the higher prosodic domain-initial positions showed enhanced durational properties compared to the lower prosodic domain-initial positions. However, the enhancing strategies were different among phonation types. Relative to lenis and aspirated stops, and lenis fricatives, tense stops and fricatives showed less consistent variation as a function of prosodic position and word type. In the perception study, the identification error rates and reaction time for same-spliced CVs were compared to those for cross-spliced CVs. Korean listeners identified the same-spliced CVs more accurately and faster than cross-spliced CVs. In addition, the distinctive acoustic properties of each prosodic domain-initial position were perceptually distinguished by Korean listeners. Due to relatively shorter duration and less distinctive contrast, the target CVs extracted from lower prosodic domain-initial positions caused more confusion in the identification of target segments. In conclusion, this study provides the evidence that speakers modulate their speech clarity depending on information content. By enhancing phonetic properties and phonological contrast, speakers tend to provide perceptual cues for prosodic positions with less contextual information. / text

Cette thèse étudie la coarticulation C-à-V en français et son interaction avec d’autres sources de variations dans le but de mieux comprendre ce qui la module et ce qui gouverne la variation dans la parole. Pour cela, à partir de grands corpus de parole, nous avons testé comment la coarticulation C-à-V était fonction : 1) des caractéristiques articulatoires des consonnes et voyelles impliquées à partir de 18.5k voyelles /i, e, ɛ, a, x, u, o, ɔ/ (/x/=/ø, œ, ə/) en contexte ALVéolaire, UVulaire et VÉLaire ; 2) de la position prosodique occupée par les voyelles, en comparant le degré de coarticulation de 17k séquences CV et VC, V=/i, e, a, ɔ/ et C=ALV|UV, en position initiale de groupe intonatif, avec celui de séquences semblables en position interne de mot ; et 3) du style de parole, en analysant le degré de coarticulation dans 22k séquences CV et VC, V= /i, E, a, u, ɔ/ (/E/=/e, ɛ/) et C=ALV|UV, issues de parole journalistique et conversationnelle. Cette thèse montre qu’en plus de dépendre des caractéristiques articulatoires des segments, la coarticulation est aussi modulée par des facteurs linguistiques, liés à l’organisation prosodique du message, et des facteurs communicationnels dépendant de la situation de communication. Cependant, certains résultats suggèrent que la modulation de la coarticulation par la position prosodique et le style de parole, ont des fonctions linguistiques différentes dont les implications sur la variation dans la parole seront discutées. Enfin, une réflexion sur les changements de sons en lien avec la préférence universelle pour l’antériorisation des voyelles postérieures fermées sera proposée à partir des différences observées entre les voyelles. / This dissertation examines C-to-V coarticulation in French and its interaction with others sources of variation in order to better understand what modulates and governs variation in speech. Based on data from large speech corpora, we tested how C-to-V coarticulation is a function of: 1) the articulatory properties of the tested segments, i.e. 18.5k vowels /i, e, ɛ, a, x, u, o, ɔ/ (/x/=/ø, œ, ə/) in ALVeolar, UVular et VELar contexts; 2) the prosodic position occupied by the vowels, comparing the degree of coarticulation of 17k CV and VC sequences V=/i, e, a, ɔ/ and C=ALV|UV in initial position of intonational phrases, to similar sequences in internal word position; 3) the speech style, by analyzing the degree of coarticulation in 22k CV and VC sequences, V = /i, E, a, u, ɔ/ (/E/ = /e, ɛ/) and C = ALV|UV, in journalistic and conversational speech. The thesis demonstrates that coarticulation, in addition to being dependent on the articulatory characteristics of segments, is also modulated by other linguistic factors, related to the prosodic organization of the message, and communicational factors depending on the communication situation. Indeed, vowels are more resistant to coarticulation in strong prosodic positions as in formal speech. However, some results suggest that the modulation of coarticulation by prosodic position and speech style have different linguistic functions whose implications for speech variation will be discussed. Finally, a reflection on sound changes related to the universal preference for the anteriorization of back closed vowels will be proposed from the observed differences between the vowels.