Portuguese and Spanish have the same origin, they are both Romace languages of West Iberian. They both find their origins in Latin. Portuguese and Spanish also have many similar words. Some times, the pronunciation of certain words are similar in both languages. If one understands one of these languages, it would be easy and quick to learn the other.
One major similarity between Portugese and Spanish is that linguists believe that they both have their origins in the Romance language of West Iberian or what is also known as Hispano Iberian. The two languages also share some of the same words. As a matter of fact is has been said that if a person becomes an advanced speaker of Spanish then they should pretty much have no problem in learning Portugese rather quickly.
The biggest similarity with Portugese and Spanish again is that they have the same origins. The words are similar and the pronunciation of the words and the accents on letters are pretty much the same. These languages are two of the most spoken all around the world and they have always been recognized as two of the most beautifully spoken as well.