質問: I just had to tell a long booking number over the phone, and realized that some characters like V/B can be hard to convey. So, I want to learn exactly how each letter is currently taught in Japanese schools. For every case where there are variants (like for H or Z), please select only one, the one that will be the most understood and induce the least amount of ambiguity when spoken as part of a meaningless booking number. Please also indicate what moras must be stressed.
回答: I share your experience. Sticking straight to the *katakana* pronunciation below, I have never had the problem of someone not understanding me any more. I believe this is the pronunciation currently taught in Japanese schools. A: エー【HL】 B: ビー【HL】 C: シー【HL】 D: ディー【HHL】 E: イー【HL】 F: エフ【HL】 G: ジー【HL】 H: エイチ【HLL】 I: アイ【HL】 J: ジェー【HHL】 K: ケー【HL】 L: エル【HL】 M: エム【HL】 N: エヌ【HL】 O: オー【HL】 P: ピー【HL】 Q: キュー【HHL】 R: アール【HLL】 S: エス【HL】 T: ティー【HHL】 U: ユー【HL】 V: ブイ【HL】 W: ダブリュー【HLLLL】 X: エックス【HLLL】 Y: ワイ【HL】 Z: ゼット【HLL】 In all cases the pitch drops after the first mora (which is high, or "stressed"). This is how you should read them as single letters or multiple unrelated letters. As an acronym, the main drop in pitch happens on the last letter only, e.g. URL ユーアールエル【LHHHHHL】. (This is just the same as in English, where the last letter is stressed, so it is not something you need to try to remember separately.)