Inclusion Criteria:  18 years or older. No diagnosis of neurological disorder (other than stroke). No diagnosis of psychiatric disorder. No seizure within the past 6 months. Not pregnant. In chronic phase of recovery, defined as at least 6 months post-stroke. Not undergoing speech and language therapy targeting auditory comprehension or attention for the duration of the study. No metal implants in the head. No unhealed skull fractures. Onset of aphasia related to left hemisphere stroke. Damaged brain tissue from stroke does not overlap with left hemisphere dorsolateral prefrontal cortex. Mild to moderate aphasia. Cognitive ability minimally within functional limits. Able to pass vision and hearing screening (with use of corrective aids if needed; eyeglasses, hearing aids). Willing to allow audio-recording of study sessions.  Exclusion Criteria:  Younger than 18 years old. Diagnosis or history of neurological disorder other than stroke. Diagnosis or history of psychiatric disorder. History of seizures within the past 6 months. Pregnant. <6 months post-stroke (however, if this is only exclusionary criterion met, participant can be re-evaluated at the 6-month mark if still interested in the study) Currently undergoing speech and language therapy targeting auditory comprehension or attention. Metal implants in the head. Currently has a skull fracture. Onset of aphasia related to etiology other than left hemisphere stroke. Damaged brain tissue includes left hemisphere dorsolateral prefrontal cortex. No aphasia or severe aphasia. Cognitive ability below functional limits. Unable to pass vision and/or hearing screening with use of corrective aids. Unwilling to allow audio-recording of study sessions.