The Queen began using those two pronunciations shortly after we set sail. Of course, I barely paid it any mind... it's a truly trivial difference, and there are plenty of native speakers who can't even differentiate them. At first, the Queen used the neutral 'bu' sound, but at some point, she began alternating between the two. The female pronunciation of 'bu', which mixes in a slight fricative sound, and the male pronunciation, which is made without bringing the upper and lower jaws together, are relatively distinct. But earlier, when the topic of Shimano came up, I recalled... wasn't it right around the time Kurapika first used his chain ability...? That made me think, 'huh?', which is how I first noticed. So that you could speak the 'truth' without making the chain swing... to prepare for the unlikely event that you were questioned by my chain. For the moment you had to say, 'he is my child'. You used them to selectively differentiate between a 'lie' and a 'boy', didn't you. ...Right now? Whose child... is he, and where is your daughter...