Switching back and forth between two different languages presents a cognitive challenge that can trip up even the most fluent bilingual speakers.
Researcher Matthew Goldrick of Northwestern University and colleagues wondered whether the disruptions caused by language-switching might extend beyond the ability to produce words to influence how bilingual speakers actually pronounce words.
They hypothesized that switching between languages might lead to accent “contamination,” whereby a speaker’s native language influences the subsequent pronunciation of words in a nonnvative language.
Goldrick and colleagues tested 10 native Spanish speakers from Barcelona, Spain, all of whom began learning English in childhood.
The participants were presented with a series of pictures that they were supposed to name in either Spanish or English, depending on the color of the frame around the picture.
Of the 32 target words, half began with voiced sounds (/d/, e.g., door, dinero) and half began with voiceless sounds (/t/, e.g., tent, toro). The researchers gauged participants’ accents by measuring voice-onset time, which typically differs between the two languages.
Participants produced more accented pronunciations of English target words when they had to switch from a previous Spanish word as opposed to continuing from a previous English word. The results were similar for words that began with voiced and with voiceless sounds.
The effect didn’t seem to work in the other direction, though — English pronunciations didn’t seem to carry over when they switched to words in their native language of Spanish.
“This finding extends previous work suggesting that placing speakers in a difficult production context can increase speakers’ accents,” the researchers write.
According to Goldrick and colleagues, the findings fit well with interactive theories of speech production — specifically, native language representations may have been more active on switch trials, causing participants to deviate away from the target language (English) toward the nontarget language (Spanish).
“Although accents partially reflect the difficulties multilingual speakers have in successfully acquiring the sound system of a nonnative language, our results add to the body of work showing that difficulties in language processing also play an important role,” the researchers conclude.
Goldrick, M., Runnqvist, E., & Costa, A. (2014). Language Switching Makes Pronunciation Less Nativelike. Psychological Science, 25 (4), 1031-1036. DOI: 10.1177/0956797613520014