<prompt> First sound by child is:SibilantBilabialFricativeMonolabial  <response>: Most children are able to produce the bilabial sounds made with the lips of b, p, m, w first, since these are sounds visible on the lips. They may also produce sounds linguo-alveolar such as d, n, t early on as well.These sounds are called linguo-alveolar, since they are produced with the tongue behind the teeth against the alveolar ridge in the mouth. 