What skills does "Word Bubbles Rising" help improve?

According to Lumosity, the creators of "Word Bubbles Rising," the game improves verbal fluency. Lumosity states that playing this game enhances a player's ability to quickly recall known words.

"Word Bubbles Rising" tests language skills and flexibility by using a unique approach to language training. The game involves guessing various words that begin with a two-, three- or four-letter stem in order to float a ship animation as high on the screen as possible. Longer words cause the bubble to move up higher. By playing this game and others that are part of the Lumosity site, individuals can significantly increase their brain performance.