Stuttering (alalia syllabaris), also known as stammering (alalia literalis or anarthria literalis), is a speech disorder in which the flow of speech is disrupted by involuntary repetitions and prolongations of sounds, syllables, words or phrases, and involuntary silent pauses or blocks during which the person who stutters is unable to produce sounds. The exact etiology of stuttering is unknown; both genetics and neurophysiology are thought to contribute. There are many treatments and speech-language pathology techniques available that may help increase fluency in some people who stutter to the point where an untrained ear cannot identify a problem; however, there is essentially no cure for the disorder at present.