Stopwords, short tokens, and nonlatin characters are currently ignored without explanation.
When you search for "the qx あああああ dog", we should provide a hint that "the" was ignored as a stopword, "qx" was ignored as a short token, and "あああああ" was ignored as non-latin (does this actually work with InnoDB fulltext?).
Ideally, we should provide an option to perform substring search instead.