 When the European tradesmen extended their market to other countries, it often occurred that a simplified form of their mother tongue was used as business language between tradesmen with different tribal and linguistic background. Such a special-purpose language is referred to as lingua franca. When the tradesmen from Europe left, the native citizens continued to use this lingua franca, now referred to as pigeon. When what originated as a pigeon becomes the native language of a group of people, a creole has developed. This typically occurs when the speakers of a pigeon marry and have children. Their children grow up with a pigeon, now referred to as creole, as their first language.