This is the 11395th most frequent Portuguese word.
neerlandês
Dutch (language or nationality of the Netherlands).
Here, 'neerlandês' is used to refer to the Dutch language as a subject of study.
Eu comecei a aprender neerlandês na escola.
I started learning Dutch in school.
In this case, 'neerlandês' is used to describe someone's nationality in Portuguese, referring to a person from the Netherlands.
O professor é um cidadão neerlandês que mora no Brasil.
The professor is a Dutch citizen living in Brazil.
Here, 'neerlandês' is used to indicate the language in which the book is written.