 In the world, approximately four times as many men as women stutter, encompassing 70 million people worldwide, or about 1% of the world's population.The impact of stuttering on a person's functioning and emotional state can be severe.This may include fears of having to enunciate specific vowels or consonants, fears of being caught stuttering in social situations, self-imposed isolation, anxiety, stress, shame, low self-esteem, being a possible target of bullying (especially in children), having to use word substitution and rearrange words in a sentence to hide stuttering, or a feeling of "loss of control" during speech.