For grammatical similarity:
* Portuguese: Portuguese is considered the closest language to Spanish in terms of grammar. They share a common ancestor, and their grammatical structures are very similar.
* Catalan: Catalan is another Romance language spoken in Spain and parts of France. It shares many grammatical similarities with Spanish, and speakers of both languages can often understand each other to some degree.
For lexical similarity:
* Portuguese: Portuguese also shares a large number of words with Spanish, making it relatively easy for speakers of both languages to understand each other.
* Italian: Italian also shares many words with Spanish, although less than Portuguese.
* French: While French is further removed from Spanish, it still shares a significant number of words, particularly in academic and scientific contexts.
For overall ease of understanding:
* Portuguese: Again, Portuguese is generally considered the easiest language for Spanish speakers to learn due to its strong grammatical and lexical similarities.
However, it's important to note that while some languages share similarities with Spanish, understanding them can still be a challenge depending on the individual's level of exposure and language learning skills.