relapse. Fluency shaping therapy Fluency shaping therapy, also known as "speak more fluently", "prolonged speech", or "connected speech", trains people who stutter to speak less disfluently by controlling their breathing, phonation, and articulation (lips, jaw, and tongue). It is based on operant conditioning techniques. People who stutter are trained to reduce their speaking rate by stretching vowels and consonants, and using other disfluency-reducing techniques such as continuous airflow and soft speech contacts. The result is very slow, monotonic, but fluent speech, used only in the speech clinic. After the person who stutters masters these skills, the speaking rate and intonation are increased gradually. This more normal-sounding, fluent speech is then transferred to daily life outside the speech clinic, though lack of speech naturalness at the end of treatment remains a frequent criticism. Fluency shaping approaches are often taught in intensive group therapy programs, which may take two to three weeks to complete. Modification therapy The goal of stuttering modification therapy is not to eliminate stuttering but to modify it so that stuttering is easier and less effortful. The rationale is that, since fear and anxiety cause increased stuttering, using easier stuttering and with less fear and avoidance, stuttering will decrease. The most widely known approach was published by Charles Van Riper in 1973 and is also known as block modification therapy. However, depending on the patient, speech therapy may be ineffective. Electronic fluency device Altered auditory feedback, so that people who stutter hear their voice differently, has been used for over 50 years in the treatment of stuttering. Altered auditory feedback effect can be produced by speaking in chorus with another person, by blocking out the voice of the person who stutters while they are talking (masking), by delaying slightly the voice of the person who stutters (delayed auditory feedback) or by altering the frequency of the feedback (frequency altered feedback). Studies of these techniques have had mixed results, with some people who stutter showing substantial reductions in stuttering, while others improved only slightly or not at all. In a 2006 review of the efficacy of stuttering treatments, none of the studies on altered auditory feedback met the criteria for experimental quality, such as the presence of control groups. Mobile applications There are specialized mobile applications and PC programs for stutter treatment. The goal pursued by the applications of this kind is speech cycle restoration: I say, I hear, I