How do French, Spanish, and Portuguese creoles differ from their source languages?

Creole languages that developed from French, Spanish, or Portuguese are distinct, full-fledged linguistic systems that emerged in colonial settings through contact between speakers of European languages and non-European languages.123

The differences between these creoles and their source languages—often called lexifiers—arise from complex processes of restructuring. Scholars generally attribute these differences to three main influences:1

• Substrate Influence: Non-European languages (such as those spoken by enslaved Africans) may have imposed their own grammatical structures onto the European vocabulary. For example, some theories suggest Haitian Creole uses French words but follows the grammar of Ewe-Fon languages.1
• Superstrate Influence: The creoles were primarily influenced by the nonstandard, colonial varieties of the European languages themselves, rather than the standard forms spoken in Europe.1
• Universalist Perspectives: Some linguists argue that creoles developed according to universal principles of language acquisition or a biological "bioprogram," where children exposed to a pidgin created new, systematic grammars.1

Ultimately, these creoles are not "corrupted" versions of their source languages but are natural, evolved vernaculars that reflect the unique sociohistorical conditions of their development.3