Inferior frontal sensitivity to common speech sounds is amplified by increasing word intelligibility

► Left inferior frontal cortex is particularly responsive to common speech sounds. ► We probed this finding by manipulating speech intelligibility and varying age. ► The most intelligible words produced the strongest frontal response to speech sounds. ► Age (19-79) did not predict the speech sound effect on inferior frontal cortex. ► These task specific frontal results suggest an associative not a recruitment impact.