Cognitive Processing Demands of Accented Speech
Natacha Moreno, M.S., CCC-SLP
An accent is part of a person’s heritage, reflecting the unique characteristics and background of an individual. While it is often a source of pride, heavily accented speech can have a downside. Even in the presence of proficient language skills, speech and intonation patterns, as well as difficulty with idiomatic speech, may interfere with clear speech and the ability to communicate effectively on the part of the speaker. In turn, the perception of the accented speech on the part of the listener also plays a role in how successfully the message is received.
During the acquisition of a primary language, an individual’s mouth has been trained to pronounce certain sounds in a certain way, and to form connected speech with a particular stress, rhythm, and intonation. Accents occur when non-native speakers transfer the patterns and features of their native language over when speaking a new language. Additionally, when the second language includes speech sounds not found in the inventory of the speaker’s native language, the foreign-accented speaker often replaces target language sounds with native language sounds.
The perception of accented speech by the listener is influenced by a multitude of factors, including the individual’s familiarity with an accent, intrinsic motivation, the listening environment, and the complexity of the language being used (Van Engen and Peelle, 2012).
Recent studies are beginning to address the cognitive effects of accented speech on the listener - specifically, whether accented sounds, coupled with stress, rhythms and intonations that don't match the English pronunciation, increase the processing demands of the listener. In a 2014 study employing functional magnetic resonance imaging (fMRI), researchers Han-Gyol Yi, Rajka Smiljanic and Bharath Chandrasekaran, observed the neural processing of native English speakers as they listened to native American English, and Korean-accented English sentences. Results from the fMRI indicated an increase in activity in the bilateral primary auditory cortices and the inferior frontal gyri, potentially reflecting that “foreign-accented speech perception places greater demand on the neural systems underlying speech perception.” (Yi, Han-Gyol, and Rajka Smiljanic, 2014).
In the article, “Listening Effort and Accented Speech,” Van Engen and Peelle, link the degree of these processing demands to what is called an “acoustic mismatch.” This refers to the difference in what an individual expects to hear (given stored phonological and lexical representations) versus what the individual is actually perceiving auditorily. In the case of heavily accented speech, there would exist a potentially significant “acoustic mismatch,” resulting in increasing cognitive processing demands and effortful listening. In turn, this effortful listening can interfere with subsequent attention, language, and memory (Van Engen and Peelle, 2012) - all processes intrinsic to effective communication.
Van Engen, Kristin, and Jonathan Peelle. "Listening Effort and Accented Speech." Frontiers. Frontiers in Human Neuroscience, 05 Aug. 2014. Web. 19 Dec. 2014.
Yi, Han-Gyol, and Rajka Smiljanic. "The Neural Processing of Foreign-accented Speech and Its Relationship to Listener Bias." Frontiers. Frontiers in Human Neuroscience, 08 Oct. 2014. Web. 19 Dec. 2014.