“…Further, these signals can be endogenously produced by a second source (for example, choral speech, shadowed speech, and masking auditory feedback (MAF)) (Kalinowski et al 1993, 2000, Cherry and Sayers 1956) or endogenously triggered such that it is dependent on one's own speech output (for example, delayed auditory feedback (DAF), and frequency‐altered feedback (FAF)) (Bloodstein and Bernstein‐Ratner 2008, Kalinowski and Dayalu 2002, Keifte and Armson 2006, Kuniszyk‐Jozkowiak and Adamczyk 1989, Kuniszyk‐Jozkowiak et al 1996, 1997, Silverman 1996, Smolka and Adamczyk 1992, van Riper 1971, Yates 1963). Finally, these second signals can be delivered via the auditory (for example, DAF, masking, and reverberation; Kalinowski et al 1993, Lincoln et al 2006), visual (for example, visual choral speech (VCS), and lights with varying on/off frequency durations; Kalinowski et al 2000, Kuniszyk‐Jozkowiak and Adamczyk 1989, Smolka and Adamczyk 1992, Snyder et al 2009), or tactile modality (for example, tactile sensors placed on the fingertips; Kuniszyk‐Jozkowiak and Adamczyk 1989, Kuniszyk‐Jozkowiak et al 1996, 1997). Overall, it should be noted that the modality of the signals and signal characteristics influences the extent of stuttering frequency reduction with auditory choral speech being the most potent signal in reducing stuttering.…”