Background: With the tremendous improvements in technology in producing new techniques to overcome stuttering, many assumptions were stated from different aspects. Aims:To in/validate some of the stuttering assumptions, the present study attempts to investigate the role played by Delayed Auditory Feedback (DAF) device in overcoming stuttering and improving stutterers' fluency. Methods:A client study of MO, a 23-year old bilingual student who exhibits stuttering and language delay due to psychological factors. An intensive therapeutic treatment which continued for 20 months has been given to the client at hand. The client had to practice (in English) ten(10) alphabetical characters, twenty (20) words (10 nouns and 10 verbs), and ten (10)sentences for four continuous hours every day. Results:The analyses of the client's utterances throughout five entire sessions show that his rate of speech became slower if not almost normal across increases in DAF. The findings reveal that simultaneous application of both treatments on speaking through DAF was successful in reducing the rate of stuttering in the speech of the client under investigation. It all depends on age, determination, the level of severity, and the way he/she uses DAF. These findings account for the results that support many theories of stuttering including Phonemic Content Theory, Covert Repair Hypothesis (CRH) and Johnson's theory. Taken together, these results weigh strongly against the hypothesis stated that stutterers have generally high levels of emotional reactivity (e.g., Brutten/Shoemaker, 1967).