It is designed to teach spelling based on the assumption that spelling is a memorization (as opposed to rule-based) task. The program presents a series of spelling words within sentences, and then requires the learner to type in the spelling words. In "learning" mode, the program would ignore incorrect letters, with the idea being that seeing an incorrect spelling on the screen would interfere with memorizing a correct spelling.
The program uses a memorization-based approach for spelling instruction, ignoring errors during learning to enhance memorization. It presents words within sentences and asks learners to type them out in "learning" mode.