Portuguese and Spanish, although closely related sister languages, differ in many details of their phonology, grammar, and lexicon. Both are part of a broader group known as West Iberian Romance, which also includes several other languages or dialects with fewer speakers, all of which are mutually intelligible to some degree.

What's the best answer to this question: is there a difference between spanish and portuguese language?

Pick your answer from:
a). no
b). yes...A:
b).