Err, once upon a time, Nintendo made a deal with Software Toolworks to make a series of educational games using the Mario Liscense. These included Mario Teaches Typing, Mario Is Missing, Mario's Time Machine, and a trilogy of games unique to the Super NES under the title "Mario's Early Years." All three titles utilized the same engine, and each game had an assortment of challenges for little kids. These mini-games differed with each series. Fun With Letters focused on spelling, reading, and so on.
The games don't shine when compared to other Super NES titles, but then again they're educational titles, and the focus is more on the content than the design. Though Mario, Yoshi, and a few other characters have their looks taken directly from Super Mario World, others are completely original sprites. Luigi's sprite was created specifically for this series, and doesn't share Mario's look. Princess also got an original sprite, as did a few characters which cameo in the game. The game is also one of the better SNES games to utilize voices. They are clear and unmuffled, and used rather heavily. In terms of play, this game was pretty unique. Although controller compatible, the game is best played using the Super NES Mouse, and makes good use of the ease of control it provides. You first select from three characters (Mario, Yoshi, and Princess), and begin your adventure. The mini-games are simple, but suitable for preschool aged children. One game involves listening to the sound of a letter, then finding the item which starts with the letter that makes that sound. For instance, when you hear the sound "cuh," then you would click on the cow, and for "i", "icky Iggy" (I kid you not). The games mix things that kids are familiar with and characters in the Mario universe (thus "icky Iggy").
Overall, these are good educational titles. My only complaint is that each mini game only has a limited number of puzzles, and the game does not last long.