The internet has changed the face of Scrabble play – there are lots of online games such as the official Scrabble game by Hasbro, and similar word games such as Wordscraper, Lexulous and Words with Friends. Each of these games offers several options for the game dictionary – which should you use when playing with friends versus playing in a tournament?
The 'Official Scrabble Players Dictionary' was originally compiled in 1978 by members of the US National Scrabble Association for use in sanctioned tournaments. For a word to be included in this dictionary it must be present in one of five standard print dictionaries – Merriam-Webster's Collegiate, Funk & Wagnalls Dictionary of the English Language, The American Heritage Dictionary of the English Language, Webster's New World Second College Edition , and The Random House College Dictionary. The current version of this scrabble list is OSPD4.
In the United States, Canada and Thailand tournament play now uses the Tournament Word List (TWL) which is a modified version of the Official Scrabble Players Dictionary. The dictionary has been edited from the original OSPD version to remove some words which are less suitable for tournament play. The removed words are those that could be considered offensive to players. The current version used in competition is TWL2, and is sometimes referred to as OWL (Official Word List).
Within the United Kingdom, Australia, and New Zealand the dictionary used is 'Official Scrabble Words' (OSW). This is a collection of all the words and combinations playable in tournament Scrabble within those countries and uses British English.
In the rest of the world, the SOWPODS dictionary is used. The SOWPODS dictionary is an amalgamation of the British OSW and National Scrabble Association's OSPD dictionary. It is not published as an actual dictionary with definitions, rather it allows for either of the OSW or OSPD dictionaries to be used as a reference when playing Scrabble.
So, which list should you use? The SOWPODS word list has the most words in it, which would give you the most possibilities to play in a friendly game. If you're practicing for a tournament or playing in a more competitive game, the official word list for your country should be used.