Background: This study examined the effectiveness of a modified version of the Motor Learning Guided (MLG) approach, a treatment protocol to establish functional speech that incorporates principles of motor learning: blocked and random practice schedules, delayed and summary knowledge of response (KR) feedback, and specificity of training. Methods: A 29-year-old male survivor of traumatic brain injury diagnosed with moderate-severe apraxia of speech (AOS) participated in this protocol. A time-series ABA design measured the participant's production of two sets of five target items, and his ability to maintain accurate productions several months after treatment. Results: Improvements were seen in the participant's ability to produce both sets of trained items; however, the second set of target items were practiced with more frequency, which may have lead to a greater accuracy of production in less time compared to the first set of five target items. Conclusions: Application of motor learning principles through the modified MLG approach can lead to increased accuracy and automaticity of trained target items, and the ability to maintain accurate phrase production following cessation of treatment. Adherence to a frequent practice schedule and other motor learning principles is influential to success of this treatment for AOS.