Spectral biofeedback has been studied in previous studies as a potential complement to traditional articulation therapy for individuals who have been resistant to traditional articulation therapy. Results from these studies have been promising in substantiating the potential of spectral biofeedback as effective complements to traditional articulation therapy. However, existing studies have only been using spectral biofeedback within the clinic setting, and most studies have only explored the use of spectral biofeedback to treat the /r/ phoneme. Therefore, the current study aims to investigate the effectiveness of spectral biofeedback for the treatment of other English phonemes. Additionally, delivery through a mobile application on an iPad allows spectral biofeedback to be portable, by enabling the individual to bring the therapy back to the home environment for practice, potentially maximising therapy effectiveness.