Lexicon-Go

From BoardGameGeek:

Though this is based on the long-established card game of Lexicon, it isn't just a new edition of the same game. The 52 letter cards of the original game are replaced here with 52 letter tiles. These can be used to play the original game but they also introduce a new speed game. This dispenses with the letter values used in the original game and it dispenses with conventional turns. Instead it is played over 5 rounds, with the winner of each round simply being the fastest player to use all 10 of his letter tiles.