Yeah, like Pensieve said, it sounds like synaesthesia. Everything I've read, and my personal experience, says that the associations are involuntary. I have no idea if this would actually work, but maybe if he made physical contact with people while holding something that he liked the taste of in his mouth, his brain would make a new association?
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Music Theory 101: Cadences.
Authentic cadence: V-I
Plagal cadence: IV-I
Deceptive cadence: V- ANYTHING BUT I ! !! !
Beethoven cadence: V-I-V-I-V-V-V-I-I-I-I-I-I-I-I-I-I-I
-I-I-I-I-I-I-I-I! I! I! I I I