Close examination reveals it to be "a polyvalent term (portuñol/portunhol) used to describe a wide range of phenomena, including spontaneous contact vernaculars in border regions, errors produced by speakers attempting to speak the second language (L2) correctly, and idiosyncratic invented speech designed to facilitate communication between the two languages.
They have almost identical syntactic structures, as well as overlapping lexicons due to cognates, which means that a single macro-grammar is produced when the two mix.
[2] An example for literary effect, "not based on accurate imitations of the speech of border regions",[2] is the phrase en el hueco de la noite longa e langue, illustrating a code-mix of the Spanish article la and the Portuguese noun noite.
[1] One important literary work written in Portuñol is Mar paraguayo by Brazilian author Wilson Bueno [pt].
In recent decades, some Portuguese-based creole languages have also become influenced by standard Spanish, notably Annobonese and the Aruban dialect of Papiamento.