The names people may use on a day to day basis are not always the same as those that they were given at birth and/or those used for official documentation. "Robert", for example, may be known as Bob, Bobby, Rob, Robby, Bert and so on. Lists of alternatives are used in data management, but they are generally specific to a single language or cultural group, and will never cover all the nick name variants that people use, as nick names may be completely unrelated to official names. Also, a single nick name may be related to multiple officla names: Ted, for example, may be a nick name for Edward or Theodore.
Assumption should never be made about a personal name. One can never assume that a person called Bob is using that as a nick name and that their official name is Robert. The "nick name" may be their official name, or be a nick name unrelated to the official name.
In The Netherlands, children are often given three or four official names at birth, and a (sometimes unrelated) roepnaam ("calling name") which they use in everyday life. In Thailand most people have nicknames they will use in everyday situations, unrelated to their official names. For example, former prime minister Thaksin Shinawatrahas had the nickname Maew (แม้ว)
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