 And so on.Maybe a native speaker of English can construct enough discovering pages for all these 217 letter-sound-combinations, but the time being Discovery Learning to Read (DLR) looks only feasible with one or more auxiliary letters.To make it clear to the child from the outset that ‘ai’ is not a standard letter but an auxiliary letter, this is told to him and this letter is presented in a different way than the standard letters, for example with a line through it and/or against a gray instead of white background