 :: I agree. There needs to be a Wikipedia-wide policy on diacritics; and in point of fact, whatever the consensus ends up being, I'd be happy to go along with it. But there does need to be a consensus across those working on all cultures. The Japan Wikiproject recently reached a consensus on our own use of macrons (the little lines over a 'u' or 'o', representing the long vowel sounds 'oo', 'ou' or 'uu'). Perhaps a discussion needs to be begun over at WP:MOS or somewhere else major and central.  