The Neuroscience of Language

This chapter provides an overview of how listeners’ brains process building blocks of speech: phonemes (that is, speech sounds) and word forms. Phonemes are processed bilaterally in posterior portions of the superior temporal sulcus. Compared to isolated phonemes, spoken words are acoustically more complex and associated with both grammatical status and meaning. Spoken word processing relies on bilateral temporal cortex, including portions of the superior temporal gyrus and middle temporal gyrus. The role of acoustic context on word recognition is also covered, including effects of speech rate and how listeners interpret speech sounds in relation to what surrounds them. Theoretical perspectives covered in the chapter include predictive coding (in which unpredicted sounds are associated with increased activity) and lexical competition (in which words with similar-sounding competitors are more difficult to understand). The hemispheric lateralization of these processes is also discussed, including the important historical development of the Wada test.