V/ U-rhythm at the reading as indicator of the speech breath function state in stutterers

In the paper the sequence of duration in acoustic signal with fundamental frequency of the speech and duration without it the following one after another is termed as Voice/Unvoice-rhythm (V/U-rhythm). In our previous papers there was found out that such rhythm's structure is described rather well experimentally with the help of the quadratic logistic mapping and Feigenbaum's scenario of route to chaos for this mapping with control parameter. This scenario consists of two "wings". The initial part of the lower "wing" of the scenario with suitable small control parameter values corresponds to U-segments in rhythm, the initial part of the upper "wing" with suitable small control parameter values corresponds to V-segments. After critical value of the control parameter these "wings" are mixed forming V/U-rhythm of a normal speech. Domain of the scenario before critical point corresponds to regular V/U-rhythm which is typical for fluency disorders as repetitions. In this domain there are regular ratio between the total durations of V and U-segments (ratio Vtotal/Utotal is approximately 3/2). In chaos domain after critical point this regularity gets lost. It is suggested to use this loss of regularity as the way and indicator of stutter correction. The breath regime without phonation variate so long as the regular ratio Vtotal/Utotal will not disappear. According to the functional composition law, this loss shows that after switching on the phonation the system will be free from stuttering. Reliable statistical data confirming theory is presented in the paper.