Some Word processors miss some errors because?

“She could sew seeds better than she could sew clothes.”

The above sentence is one that I came across while reading a self-published novel the other day, and is a perfect example why one cannot merely rely on a spell-checking program to ensure that one’s writing is error-free. Although “sew” and “sow” are homophones (they sound the same despite having different spellings and meanings), they are obviously not interchangeable: When you write phrases such as, “In miss you,” “I’ll pick the care up from the garage,” or, “We’re having meet for dinner,” SpellCheck doesn’t catch any errors, because none of the words are actually misspelled. The same thing goes for Word and other word-processing softwaresow seeds, and sew clothes.