Recent Research Projects

• 2015: The behaviour of vowel quantity contrasts when speaking rate is increased and durations tend to be compressed. What is the effect of speaking rate on the compression and expansion of segment durations in Non-Pathological Perturbed Speech?

Presentation & Article: Phonemic Quantity Contrasts in Normal and Non-pathological Perturbed Speech. In The Scottish Consortium for ICPhS 2015 (Ed.), Proceedings of the 18th International Congress of Phonetic Sciences. Glasgow, UK: the University of Glasgow. ISBN 978-0-85261-941-4. Paper number 0715.1-4. 

• 2014: Relationship between ATR Vowel Harmony and Vowel Quality in Twi.

Presentation: ATR Vowel Harmony and Vowel Quality: Are They Related? 45^th Annual Conference on African Linguistics, University of Kansas April 17-19, 2014. Theme:  “Africa’s Endangered Languages: Documentary and Theoretical Approaches”.

• 2013-2014: The effects of Lexical Tone Contrasts on Vowel Quality. Acoustic measurements carried out to investigate for differences between vowel quality in the two phonological (High Tone/Low Tone) categories. Fundamental frequency values as well as formant values (F1, F2, F3 and F4) examined to determine qualitative differences between the two phonological classes.

Article: Relationship between Lexical Tone Contrasts and Vowel Quality, European Scientific Journal, vol. 10, No. 17: 418-428, 2014.

• 2011: Speech Perception: Discrimination of Twi Lexical Contrasts based on Tones by Native French Speakers.

Article: Discrimination des tons lexicaux du twi par des locuteurs français, ed. R. Sock, N. Moritz, A. Hamm, Revue des Recherches Anglaises & Nord-Américaines (RANAM), Hors Série, Service des Publications et Périodiques, Université de Strasbourg : 83-90, 2011. 

• 2010-2011: Speech Production: Nasal-Oral Contrast of Short and Long Vowels in Twi. Acoustic analyses are undertaken to compare the production of oral and nasal vowels in both the short and long categories. Durational analyses of oral and nasal short/long vowels are made. Formant structure investigations are undertaken for the two phonological classes.

Article: Nasal-Oral Contrast of Short and Long Vowels in Twi: An Acoustic Study, Selected Proceedings of the 40th Annual Conference on African Linguistics, ed. Eyamba G. Bokamba et al., 95-104. Somerville, MA: Cascadilla Proceedings Project, 2011.

Other Research Activities

• Centre National de la Recherche Scientifique (CNRS), Délégation Alsace, Assistant en production et analyse de données: The French National Centre for Scientific Research, Data Production and Analysis: February-March 2010.
• Centre National de la Recherche Scientifique (CNRS), Délégation Alsace, Assistant en production et analyse de données: The French National Centre for Scientific Research, Data Production and Analysis: June-July 2009.
• Centre National de la Recherche Scientifique (CNRS), Délégation Alsace, Assistant en production et analyse de données: The French National Centre for Scientific Research, Data Production and Analysis: May-June 2008.
• French Ministry of Research and New Technologies: Data base Project n° ACI –TTT.

Participant in the project at the Phonetics Institute, University of Strasbourg, France.

Project title: Elaboration of a multimedia platform for analysing and promotion of X-ray films data on speech production and perception made at the Strasbourg Institute since the 1950s. The project dealt with 20 films concerning various linguistic aspects of languages spoken in Africa, Europe, Asia and Latin America.

Date: 2005 to 2008.

Duration: 36 months.

• Upper Rhine (Rhin Supérieur) INTERREG III DANOK Project n° 4b 11.

Participant in the project at the Phonetics Institute, University of Strasbourg, France.

Project title: Data base, digitizing and preparation for archiving and broadcasting of rare X-ray films made over several years at the Strasbourg Institute related to cultural projects of the Upper Rhin Region. The films cover a wide variety of languages (10 African, 1 Latin American, 5 Asian, 6 European including French).

Project realization zone: France, Switzerland, Germany.

Date: July 2006 to September 2007

Duration: 15 months.

•  Acoustic Properties of five Nasal Vowels, i.e. two front high vowels, two back high vowels and one low vowel. Durational and formant value analyses: 2006.
• Preliminary Study: Do high and low tones, which exhibit different fundamental frequency (Fo) values, show qualitative (F1, F2, F3) as well as syllabic durational differences? Some phonological aspects of Twi tones are described. Preliminary acoustic measurements are carried out to investigate for differences in quality in the high and low tone categories: 2006.
• +ATR vs. –ATR Nasal Vowel Harmony. It investigates acoustic properties of the Twi nasal vowel counterparts of the four high oral vowels investigated in a previous study. Acoustic measurements are carried out to investigate for differences between vowel quality in the two phonological classes: 2006.
• Relationship between Advanced Tongue Root (ATR) Vowel Harmony and Vowel Quality. Acoustic investigations are carried out on three formants (F1, F2, F3): 2005-2006.
• Vowel Quantity Contrasts: Evidence from the five Twi Nasal Vowels: Absolute duration measures as well as relative duration values and post-vocalic consonant durations are investigated to determine the relevance of both nasal vowel and consonant durations in distinguishing the two phonological classes: 2005.
• Duration and Quality in the Production of Oral and Nasal Vowel Length Contrasts, absolute durational as well as formant value analyses: 2005.
• Advanced Tongue Root (ATR) Vowel Harmony in Twi. Preliminary acoustic measurements are carried out to investigate for differences in vowel quality between the (+ATR) and the (-ATR) groups: 2004.
• Motor Control in Speech Production and the Perceptual Efficiency of Anticipatory Gestures: Acoustic Data Analysis of Labialized Vowels: 2004.
• French Ministry of Research and New Technologies: Cognitive Project n°ACT 1b.

Participant in the project at the Phonetics Institute, University of Strasbourg, France.

Project title: Motor Control in Speech Production and Perception of Anticipatory Gestures.

Date: 2001 to 2003.

Duration: 24 months.    

• Preliminary Study: Relationship between Vowel Quantity and Vowel Quality. Acoustic investigation of durational and qualitative (F1, F2, F3, F4) differences: 2003.
• Vowel Quantity Contrasts: Building upon the previous work on the three extreme vowels of the Vowel Triangle, this study carries out an acoustic investigation of the remaining six Oral Vowels of Twi belonging to the two phonological (short and long) classes: 2003.
• A Cross-Language investigation of Phonemic Frequency in Twi, French and English. The methodology of this study of quantitative phonology consists of comparative analyses of phonemic frequency and statistical treatment of various phonemes based on a wide range of material from the three languages: narrative, musical texts and minimal pairs: 2002.
• Phonemic Frequency in French and Twi with a View to a Didactics Application. Put in a pedagogico-didactical perspective, this study anticipates a contribution to phonetic training in second language acquisition e.g. lexical entries in language acquisition: 2001.
• Vowel Quantity Contrasts in Twi: acoustic durational investigation involving short and long categories of the three extreme vowels of the Vowel Triangle. Absolute duration measures as well as relative values and post-vocalic consonant durations are investigated to determine the relevance of both vowel and consonant durations in distinguishing the two phonological classes: 2000.

2016-2017: Contribution to the Illustrations of the International Phonetic Alphabet. This contribution will be the first Ghanaian Language (Twi) to appear in the series of more than 110 languages. Illustrations will be accompanied at the time of submission by high-quality recordings (preferably WAV files) with at least a 22 kHz sampling rate, of all words and narrative text in the target language occurring anywhere in the illustration. Acoustic recordings are made at 44.1 kHz sampling frequency or higher, and with a bit-rate of 16 bits or higher.

2018-2019: How native speakers of French, a non-tone language with different lexical stress properties, perceive two Twi lexical tones in a series of monosyllabic contrasting words. They are words produced, first in isolation and second, in a carrier sentence. Three experiments were conducted. Experiment 1 tested identification of tone contrasts by native speakers of Twi. Experiment 2 tested native French speakers’ identification of tones presented in isolated context and Experiment 3 tested identification of tones presented in a carrier sentence. Acoustic investigations show that pitch difference is the determining factor in distinguishing high and low tone contrasts in Twi. Findings imply that linguistic experience with non-native tones does not necessarily preclude tone perception. Results also show that the identification rate of tones in an isolation context was higher than the identification rate of tones in a carrier sentence context.

Presentation & Article: Non-native Speakers’ Identification of Lexical Tone Contrasts, Proceedings of the 19th International Congress of Phonetic Sciences. Melbourne, Australia, 2019.