They aren’t. A brief note on Language Log (WordPress.org) about the dominance of U.S. spelling bees by South Asian students elicited this comment; some time back, Thais dominated, many of whom did not otherwise command English.
And it is this sort of thinking that dominates legacy methods of teaching foreign languages: just memorize lots of words and endings and you’ll have it.
Pat’s Polemics
On-going brilliance
