Well spelling was solved even earlier than that, with rote-learning at school in combination with the very environmentally friendly technologies known as the paddle and cane. What was wrong with that way of doing things?? Is it progress? Or were things better in the old days?

In any case, all the words in the sentence in question are spelt correctly - the problem is grammar. Correctly determining if the grammar of a sentence is correct is a much harder problem than simply checking the spelling of words against a dictionary.