I downloaded this for my 5-year-old daughter and 2-year-old son, both of whom are in a Montessori program. My daughter loves the sandpaper letter "tracing", which is much more difficult on an iPad than in real life, so it keeps her interested. Even the sound/letter recognition, which she knows backwards and forward, keeps her engaged because shes on the iPad. For the most part, its a bit junior for her, though. Shes ready for the "next level", which I hope will come out soon. You know...WORDS not just sounds. (The only reason I didnt give it 5 stars is that I thought it should go one more level to create 2- or 3-letter words, at least.) The 2-year-old has been introduced to the sandpapaer letters in school, but he doesnt have the manual dexterity required to be succesful at in on the iPad. Within the next couple of months, though, this will be great for him. I definitely recommend this whether or not your child is in a Montessori program.
freccles about Montessorium: Intro to Letters