Aooʼ! I think this is the first approach, so they wanted to introduce the prefixes shi-, ni-, and bi-, before the pronouns. It seems that they cannot still add all the subject pronouns because this first set of words is fixed and they cannot change it or add more words in this first stage. Still, I think some Navajo words would be edited, and also the English translations can be added or changed. :)
My doesn't work as a translation unless it's wanting us to learn individual word parts - but none of the other language packs have us learn words like "my" or "ton" or "mi" in isolation. Is it the first person singular pronoun? If so, it would be more clear - as far as learning the language goes - if "I" was the answer.