Speech Production

Speech production is central to human communication and culture, and its abnormal development or breakdown may compromise people’s quality of life. Therefore, understanding the processes underlying this fundamental human ability is of great importance.

 

Current Work.

How does learning to read shape the neural representation of spoken and written language?

Learning to read requires acquiring mappings from orthography onto existing phonological and semantic representations. Languages vary in the way that writing expresses the sounds and meanings of spoken language. Alphabetic languages (e.g. English) contain information about phonological structure within the orthography due to regular systematic relations between graphemes and phonemes. Logographic languages (e.g. Chinese) encode less fine-grained information about phonological structure via more arbitrary mappings between characters and syllables. Thus, alphabetic writing systems exhibit higher orthographic transparency. Such differences in orthographic structure impacts on the nature of reading acquisition, as well as wider impacts on existing spoken language systems (e.g. Rastle et al., 2011).

During his PhD, Adam Jowett, alongside Jo Taylor, Angelika Lingnau, and Kathy Rastle, is using artificial orthography methods to investigate how the nature of the writing system impacts on reading acquisition, and on the spoken language representations that underpin reading. Participants are trained over 10 days on two artificial languages with alphabetic and logographic writing systems in which words are denoted by visual, spoken, and semantic components. Behavioural training and testing data, and univariate fMRI analyses, suggest that different strategies are used to learn alphabetic and logographic languages.

Subsequent analysis plans include use of representational similarity analysis to investigate whether the neural representations of spoken trained words are more phonemically structured when associated with alphabetic compared to logographic writing systems. Neural representations of written trained words will also be examined to investigate whether there are differences in orthographic structure (e.g. representation of letter identity and position) for alphabetic compared to logographic writing systems. Prediction matrices will be constructed based on shared features of spoken or written words within each artificial language. These will be correlated with corresponding neural dissimilarity matrices, within regions processing spoken and written language. Findings will reveal whether phonological and orthographic representations are shaped by the nature of the writing system.

                                                                                                                                         

Key Reference:

Rastle, K., McCormick, S. F., Bayliss, L., & Davis, C. J. (2011). Orthography Influences the Perception and Production of Speech. , 37(6), 1588–94. [PDF]

Previous Work.

Generation of Abstract Phonological Codes & Articulatory Implementation.

No psychological theory can fully explain the entire process of speech production in a coherent framework that integrates the cognitive processes involved in the computation of abstract codes for sounds with the articulatory processes involved in their implementation in space and time. Funded by a British Academy fellowship, Betty Mousikou aimed to develop such a theory by investigating the relationship between the generation of abstract phonological codes and their articulatory implementation, using an innovative multidisciplinary approach that combines methods from experimental cognitive psychology and experimental phonetics. This work has major implications for theories of language processing and will improve our understanding of clinical disorders of speech production.

Key References:

Mousikou, P., & Rastle, K. (2015). Lexical frequency effects on articulation: A comparison of picture naming and reading aloud. [Special Issue on ‘Bridging reading aloud and speech production’]. Frontiers in Psychology. 6:1571. doi: 10.3389/fpsyg.2015.01571 [PDF]

 

Mousikou, P., Kinoshita, S., Wu, S., & Norris, D. (2015). Transposed-letter priming effects in reading aloud words and nonwords. Psychonomic Bulletin & Review, 22, 1437–1442. [PDF]

Mousikou, P., Strycharczuk, P., Turk, A., Rastle, K., & Scobbie, J.M. (2015). Morphological effects on pronunciation. 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 0816. [PDF]

Mousikou, P., Rastle, K., Besner, D., & Coltheart, M. (2015). The locus of serial processing in reading aloud: orthography-to-phonology computation or speech planning? Journal of Experimental Psychology: Learning, Memory, and Cognition, 41, 1076-1099. [PDF]

Mousikou, P., Roon, K. D., & Rastle, K. (2015). Masked primes activate feature representations in reading aloud. Journal of Experimental Psychology: Learning, Memory, and Cognition, 41, 636-649. [PDF]