Based on the information given, the Gullah can be described as Creole - a language that is African and American.
<h3>What is Creole?</h3>
Creole is the term that is used to define the mother tongue of Creoles. Creoles are people of mixed European and Black Descent.
Many Creoles can be found in the Caribbean. Any language that is formed by mixing a local language with any European language (such as French, English or Portugues)
Base on the question that is asking to identify the language that is used by the author in a story and base on mu further investigation and research, I would say that the answer would be a Figurative Language. I hope you are satisfied with my answer and feel free to ask for more if you have question