differences by region Researchers Bryant and Barrett (2007) have suggested (as have others before them, e.g., Fernald, 1992) that CDL exists universally across all cultures and is a species-specific adaptation. Other researchers contend that it is not universal among the world's cultures, and argue that its role in helping children learn grammar has been overestimated, pointing out that in some societies (such as certain Samoan tribes), adults do not speak to their children at all until the children reach a certain age. Furthermore, even where baby-talk is used, it has many complicated grammatical constructions, and mispronounced or non-standard words. Other evidence suggests that baby talk is not a universal phenomenon: for example Schieffelin & Ochs (1983) describe the Kaluli tribe of Papua New Guinea who do not typically employ CDS. Language acquisition in Kaluli children was not found to be significantly impaired. The extent to which caregivers rely on and use CDS differs based on cultural differences. Mothers in regions that display predominately introverted cultures are less likely to display a great deal of CDS, although it is still used. Further, the personality of each child experiencing CDS from a caregiver deeply impacts the extent to which a caregiver will use this method of communication. CDS has been seen in languages such as Japanese, Italian, Mandarin, British English, American English, French, and German. This is the basis for claims that CDS is a necessary aspect of social development for children. Although found in many cultures, CDS is far from universal in terms of style and amount of use. A factor found to influence the way adults communicate with children is the way the culture views children. For example, if they view children as helpless and unable to understand, adults tend to interact with children less than if they believe that children are capable of learning and understanding. Often, cultures lacking a form of CDS make up for it in other ways, such as involving the children more in everyday activities, though the reverse might also be a valid assessment. Vocabulary and structure Vocabulary With respect to English-speaking parents, it is well-established that Anglo-Saxon or Germanic words tend to predominate in informal speech registers, whereas Latinate vocabulary is usually reserved for more formal uses such as legal and scientific texts. Child-directed speech, an informal speech register, also tends to use Anglo-Saxon vocabulary. The speech of mothers to young children has a