Scrabbly
Playing Scrabble in Spanish isn't the same as in English. These are the differences that affect your strategy the most.
Tile distribution
Spanish has many more vowels (12 A and 12 E) and adds the Ñ. English spreads its consonants differently and uses no accents or Ñ.
Letter values
Some values differ: the H is worth 4 in Spanish, and letters like K and W are very rare. Memorise the table for the language you play.
Dictionary
Each language validates with its own dictionary. On Scrabbly you pick Spanish or English when creating a game, and the whole interface is translated to both.
Create a game in your favourite language and test your vocabulary.