If referring to the legendary island of Antilia (Antillia), or otherwise known as "Isle of Seven Cities" (Ilha das Sete Cidades or Septe Cidades in Portuguese), it'd be mainly Iberian (Spanish) and possibility of the Basque language to it as well...? But definitely Spanish.
An Antillean is a native or resident of the Netherlands Antilles.
Antillean Piculet was created in 1866.
Antillean Siskin was created in 1868.
Antillean Crested Hummingbird was created in 1758.
Lesser Antillean Macaw was created in 1905.
Lesser Antillean Tanager was created in 1834.
Antillean Adventist University was created in 1957.
Antillean Cave Rail was created in 1918.
Netherlands Antillean guilder was created in 1892.
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Netherlands Antillean.
Why,yes they are!