Manual circumlaryngeal therapy (manual laryngeal musculoskeletal tension reduction) was used to treat 25 consecutive functional dysphonia patients. Pre- and post-treatment audio recordings of connected speech and sustained vowel samples were submitted to auditory-perceptual and acoustical analysis to assess the immediate and long-term effects of a single treatment session. To complement audio recordings, subjects were interviewed in follow-up regarding the stability of treatment effects. Pre- and post-treatment comparisons demonstrated significant voice improvements. No significant differences were observed between post-treatment measures, suggesting that vocal gains were maintained. Interviews revealed 68% of subjects reported occasional partial recurrences, typically less than 4 days in duration, which resolved spontaneously. These results replicate and extend previous research suggesting the utility of manual circumlaryngeal therapy for functional voice disorders.