Closest in terms of mutual intelligibility:
* Portuguese: Portuguese and Spanish speakers often have a high degree of mutual intelligibility, meaning they can understand each other to a significant extent. This is due to their shared Latin origins and many shared vocabulary and grammatical structures.
* Catalan: Though Catalan is more distantly related to Spanish, it also shares a lot of vocabulary and grammar, especially in its written form. In some cases, Catalan speakers can understand Spanish fairly well.
Closest in terms of linguistic proximity:
* Portuguese: Linguistically, Portuguese and Spanish are considered the closest Romance languages. They belong to the Ibero-Romance branch and share a common ancestor.
Closest in terms of cultural influence:
* Portuguese: Again, Portuguese and Spanish have historically shared a strong cultural connection, leading to significant linguistic influence.
Other Considerations:
* Galician: This language, spoken in northwestern Spain, is even closer to Portuguese than Spanish.
* Aragonese: This language, spoken in northeastern Spain, is also closely related to Spanish.
* Other Romance languages: While less close than Portuguese or Catalan, Spanish also shares similarities with other Romance languages like Italian, French, and Romanian.
Ultimately, the answer to "closest" depends on how you define "closest." If you're looking for the language with the highest degree of mutual intelligibility, Portuguese is likely the answer. However, if you consider linguistic proximity or cultural influence, the answer may be different.