What is a creole, and how does one form?
A creole is a fully developed natural language that emerged from a pidgin — and the distinction between the two is one of the clearest and most interesting in linguistics.
A pidgin arises when groups with no common language need to communicate, typically for trade, labour or administration. It is a simplified contact language: limited vocabulary drawn mostly from the dominant group's language, reduced grammar, no complex clauses, and considerable variation between speakers. Crucially, a pidgin has no native speakers — everyone who uses it has another first language.
A creole is what happens when children are born into a community using a pidgin and acquire it as their first language. In doing so they do something remarkable: they systematise it. The vocabulary expands, consistent grammar emerges, tense and aspect marking develops, embedded clauses appear, and the result is a language with the full expressive capacity of any other.
Why this is theoretically important. The children are not copying a complete grammar, because there was none to copy. They generate structure that was absent from their input. Derek Bickerton's language bioprogram hypothesis proposed this as evidence of innate grammatical capacity, noting that creoles arising independently across the world share structural similarities. The hypothesis is contested — alternative explanations point to substrate influence from speakers' original languages and gradual development over more generations than Bickerton allowed — but the underlying observation is not disputed.
Examples: Haitian Creole (French-based, roughly 12 million speakers), Tok Pisin (English-based, an official language of Papua New Guinea), Jamaican Patois, Sranan Tongo, Cape Verdean Creole.
An important correction. Creoles are frequently dismissed as "broken" or "simplified" versions of European languages. They are not. They have complete, rule-governed grammars — often with distinctions the lexifier language lacks — and the perception reflects social prejudice about their speakers rather than any linguistic property.
Nicaraguan Sign Language emerged similarly in the 1980s and is closely studied.