What theories of dyslexia have not been able to convincingly explain, say the researchers, is why there is no evident difficulty in the ability to perceive and produce speech among people with dyslexia. This is especially curious if the ability to recognize phonological sounds is impaired.
The results suggest that the source of a phonological deficit might be in dyslexic individuals' difficulties learning the consistent properties of speech sounds as spoken by an individual talker.
"Lots of research has shown that individuals with dyslexia have more trouble understanding speech when there is noise in the background," says Perrachione. "These results suggest that trouble following a specific voice might be part of the cause. Teachers and other educators can be sensitive to this during classroom instruction where noise from other classmates might make it disproportionately difficult for children with dyslexia to follow what is going on in a lesson."