This is a preliminary study focused on analyzing the acoustic characteristics of stuttered speech before, during, and after a short treatment using the Smooth Speech protocol. Smooth Speech technique, among other strategies, teaches stutterers to consciously control air‐flow during speech through continuous airflow, gentle onsets for vowels, and soft contacts with consonants and to synchronize speech phrasing structure with the breath stream. In our case study Smooth Speech was shown to have a noticeable impact on the intelligibility and fluency of the speaker’s speech immediately following training. This study is a preliminary investigation to understand the phonetic features, both segmental and supra‐segmental, that were specifically effective in increasing speech intelligibility. Speech samples included a monolog a read passage for both pre‐test and post‐test sessions, and a monolog for the training period. Acoustic analysis included evaluation of phoneme duration, syllable duration, pause durations, a...