Difficulty in Speech Flow usually with repetition of syllables or words or with elongation of phonemes or blocking at the beginning or middle of words. It may be accompanied by muscular facial contractions and increased psychological tension. Many children (up to 40%) in preschool age go through a normal phase of speech fluency. Of these, 80% exceed it without any intervention at all. In 1% of all children, however, this difficulty results in a disorder (stuttering, tachycardia).