Information:  - Socialization is a term used by sociologists, social psychologists, anthropologists, political scientists, and educationalists to refer to the lifelong process of inheriting and disseminating norms, customs, values and ideologies, providing an individual with the skills and habits necessary for participating within their own society. Socialization is thus "the means by which social and cultural continuity are attained".  - An anthropologist is a person engaged in the practice of anthropology. Anthropology is the study of various aspects of humans within past and present societies. Social anthropology and cultural anthropology study the norms and values of societies. Linguistic anthropology studies how language affects social life. Biological or physical anthropology studies the biological development of humans.  - Specific developmental disorders are disorders in which development is delayed in one specific area or areas , and in which basically all other areas of development are not affected . Specific developmental disorders are as opposed to pervasive developmental disorders that are characterized by delays in the development of multiple basic functions including socialization and communication .  - The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), refers to a group of five disorders characterized by delays in the development of multiple basic functions including socialization and communication. The pervasive developmental disorders are pervasive developmental disorder not otherwise specified (PDD-NOS), which includes atypical autism and is the most common; autism, the best-known, now understood to be part of a spectrum; Asperger syndrome; Rett syndrome; and childhood disintegrative disorder (CDD).  - A sign is an object, quality, event, or entity whose presence or occurrence indicates the probable presence or occurrence of something else. A natural sign bears a causal relation to its objectfor instance, thunder is a sign of storm, or medical symptoms signify a disease. A conventional sign signifies by agreement, as a full stop signifies the end of a sentence; similarly the words and expressions of a language, as well as bodily gestures, can be regarded as signs, expressing particular meanings. The physical objects most commonly referred to as signs (notices, road signs, etc., collectively known as signage) generally inform or instruct using written text, symbols, pictures or a combination of these.  - A society is a group of people involved in persistent social interaction, or a large social grouping sharing the same geographical or social territory, typically subject to the same political authority and dominant cultural expectations. Societies are characterized by patterns of relationships (social relations) between individuals who share a distinctive culture and institutions; a given society may be described as the sum total of such relationships among its constituent members. In the social sciences, a larger society often evinces stratification or dominance patterns in subgroups.  - Rett syndrome (RTT), originally termed cerebroatrophic hyperammonemia, is a rare genetic postnatal neurological disorder of the grey matter of the brain that almost exclusively affects females but has also been found in male patients. The clinical features include small hands and feet and a deceleration of the rate of head growth (including microcephaly in some). Repetitive stereotyped hand movements, such as wringing and/or repeatedly putting hands into the mouth, are also noted.  - Communication (from Latin "commnicre", meaning "to share") is the act of conveying intended meanings from one entity or group to another through the use of mutually understood signs and semiotic rules.    What is the relationship between 'specific developmental disorder' and 'neurological disorder'?
subclass of