Traditional speech training methods can prove cumbersome because of the difficulty of providing the subject with good feedback, maintaining her/his motivation over long periods and stabilising the improvement in articulation. In this work we provide visual feedback based on displaying a trajectory in a 2-Dimensional 'phonetic space'. Data are presented from a small-scale efficacy study, which illustrate the use of OLT in speech therapy for misarticulated sibilant fricatives. Results for the contrasting articulations are compared and the potential of OLT as a therapeutic technique is discussed.