>> To me, there's a clear distinction between aural and oral, but horse >> and hoarse are identical. >In this vein, any thoughts on "buoy"? >Many say "boo-ey", yet they say "life-boy", "boy-ant", etc. >I say it as "boo-oy" but with an extremely attenuated "oo"; I >think it must sound slightly different from the way I say "boy", >but I'm not sure.One needn't be careful of one's pronunciation unless there's (perceived) danger of misapprehension. We can change all kinds of parameters (and do, constantly) when we are confident that our audience can figure it out from the rest of the utterance. That's why there's so much redundancy in language (well over 50%, of all sorts); it's a feature, not a bug. Though computational linguists don't always see it that way.
Most English speakers pronounce oral and aural the same in isolation. But when they contrast, as they do in The Oral/Aural Method and the like, we'd feel silly implying a binary contrast between two uses of the same word, so we try to pronounce one different. The rarer is the one we can modify with impunity, so I've heard variations of /awr@l/, /owr@l/, /ar@l/, and others that can't be represented on an ASCII screen. Oral is simply /or@l/, with tense/lax neutralization before /r/, which also limits the possible variation in aural.
Similarly with buoy. Luckily, the references of the two words boy and buoy are quite different, unlike oral and aural, so we can rely more on context to disambiguate. This is especially true in compounds like lifebuoy and breeches buoy (though I admit I don't know whether breeches should rhyme with itches or teaches).
So that explains why buoyant is /boy@nt/; there's no reason for it not to be. Buoy in isolation might be confused with boy, so careful enunciators might want to distinguish them. However, the most obvious pronunciation uses a diphthong /uy/ that's not very common in English, so what happens is that usually an epenthetic /w/ is inserted, producing a word of one and a half syllables /búwi/, with about the same structure and timing as Bowie /bówi/.
That's if they're careful, mind. Most people aren't, unless they need to be; and they don't know whether they need to be most of the time, because that's dependent on what their audience actually hears, and what they expect to hear, which can be guessed, and approximated, and even anticipated and timed exactly (listen to any good comedian).
But usually it isn't.