Sorry I'm afraid I don't know sign language.
Anyway: there's a huge difference between European Spanish (Castellano) and the South American varieties. For example: "Que haces?" (What are you doing?) - the letter "c" in European Spanish is pronounced very similar to the English silent "th" as in "I think.". In the South American varieties it is a softer "S".
The differences between European Portuguese and Brazilian Portuguese are even more. Portuguese people only understand the Brazilian variety(s) because TV is filled with "telenovelas" from Brazil and of course the country is filled with Brazilians mostly coming from the poorest parts of Brazil, to live a better life in a European country where they speak the same language. Not quite.
Funny thing: Brazilian Portuguese is quite close in pronounciation to German (that's why I am frequently asked if I'm Brazilian) - whereas European Portuguese is NOT. It manages the almost impossible: to emphasize "closed" vowels. It's like the words are not coming out, but they stay in your throat. Once you get used to it, many other languages sound like machinegun fire (such as my native German).
...just my usual ramblings...