Introduction
Speech Defects are any imperfect verbal utterances that occur even when the message being expressed has been properly formulated in the individual’s mind and are linguistically intact. They represent the most prevalent type of communication disorder found in humans. They may result from (1) maldevelopment or damage within the nervous system; (2) maldevelopment or damage in the peripheral structures producing speech; (3) faulty learning; and (4) functional disruptions arising from other causes. Lisping is one of the most common types of articulatory defects caused by faulty learning and, in some cases, can be related to concomitant disorders in the hearing mechanism, such as impairment in auditory acuity or auditory discrimination. Lisping is the incorrect pronunciation of certain sounds, chiefly /s/ and /z/, in the ordinary speech (Encyclopedia Americana). The most common type of error involves the substitution of a surd (voiceless) th sound for s and a sonant (voiced) th for z. Similar sound substitutions may occur for sh and ch. All of these articulatory substitutions are often classified as lisps. In some cases the tongue protrudes through the aperture of the teeth, producing what is called an interdental lisp or frontal lisp. In other instances the tongue tip does not protrude between the teeth but may maintain a firm contact against the upper teeth or the frontal part of the hard palate, while the air stream is forced around one or both sides of the upthrust tongue, producing a lateral lisp. Finally, there is the palatal lisp which is not found in typical speech development. Here, the mid-section of the tongue comes in contact with the soft palate, quite far back. Nevertheless, lisping as an isolated speech characteristic does not usually reduce the person’s intelligibility unduly. Most people can easily understand what the person with a lisp is saying. This study is being proposed to determine the