Neerlandés vs. holandés
The Spanish words 'neerlandés' and 'holandés' both refer to the Dutch language and people, but they have slightly different usages and connotations.
Neerlandés
'Neerlandés' is the more formal and technically correct term for Dutch language and people from the Netherlands.
El idioma neerlandés es oficial en los Países Bajos.
(The Dutch language is official in the Netherlands.)
Ella estudia literatura neerlandesa en la universidad.
(She studies Dutch literature at the university.)
Holandés
'Holandés' is the more commonly used term in everyday Spanish, though it technically refers only to people from the regions of North and South Holland.
Mi amigo holandés vive en Ámsterdam.
(My Dutch friend lives in Amsterdam.)
Me encanta el queso holandés.
(I love Dutch cheese.)
Summary
While 'neerlandés' is the more accurate term for Dutch language and people from the entire Netherlands, 'holandés' is more commonly used in everyday Spanish. 'Neerlandés' is preferred in formal or academic contexts, while 'holandés' is more prevalent in casual conversation and general references to Dutch culture.