I disagree vehemently with the idea that the rule has so many exceptions that it is not worth teaching. Where the i/e combination forms a dipthong, it should be obvious to anyone who pronounces the word correctly which combination is required. The base rhyme "I before E after 'C' and in words which sound like 'A,' ... like neighbor, weigh, etc" covers most of the common words. The remaining exceptions are easily memorized. At least I have found this to be the case in American English. If we have completely succumbed to the sloth tendency that any pronunciation and definition is acceptable, then I stand corrected. {;^D)