Deciduous teeth first teeth seen in the mouth are the mandibular centrals and the last are the maxillary second molars. The primary teeth are made up of central incisors, lateral incisors, canines, first molars, and secondary molars; there is one in each quadrant, making a total of four of each tooth. All of these are gradually replaced with a permanent counterpart except for the primary first and second molars; they are replaced by premolars. The replacement of primary teeth begins around age six, when the permanent teeth start to appear in the mouth, resulting in mixed dentition. The erupting permanent teeth cause
Language acquisition by deaf children but do not use sign language have better communication outcomes and social well-being than Deaf children who use sign language. The general stages of language acquisition are the same whether the language is spoken or signed. There are certain unique features of sign language acquisition due to the visual/manual modality and these differences can help to distinguish between universal aspects of language acquisition and aspects that may be affected by early experience. The very earliest linguistic tasks facing newborns are perceptual. Babies need to determine what basic linguistic elements are used in their native language to create words (their phonetic