The purpose of this study is to determine whether the effect of treatment for acquired speech impairment can be enhanced by combining effective behavioral treatment with non-invasive brain stimulation. Transcranial direct current stimulation (tDCS), which delivers low-intensity current to the scalp, and is a safe and well-tolerated approach that poses a non-significant risk to participants. tDCS provides low intensity neural stimulation which has been shown to facilitate motor learning in other domains of stroke rehabilitation such as arm motor learning but the potential to enhance speech motor learning has not been explored. This will be examined with a series of single-case experimental designs.

Inclusion Criteria:

• Right-handed
• Monolingual (English)
• Single left-hemisphere CVA
• A minimum of six months post-stroke
• Clinical diagnosis of apraxia of speech
• Normal speech perception
• Passing score on the hearing screening.

Exclusion Criteria:

• Diagnosis of laryngeal voice disorder
• Dysarthria
• History of speech impairment prior to CVA
• Presence of potential tDCS risk factors: damaged skin at site of stimulation;
• Presence of electrically or magnetically activated implant (including pacemaker);
• metal in any part of their body;
• history of medication-resistant epilepsy in the family;
• past history of seizures or unexplained spells of loss of consciousness.