hehe If you're implying that I am a linguist, or speech therapist: I certainly appreciate the sentiment! -- I guess you could say I'm an amateur linguist, and lyric-interpretation enthusiast.
I personally feel that songs with subjective / generalized meanings, or that are loaded with double entendres have a better chance of being successful by appealing to a wider culture-base; and the artists that write them are brilliant.
If you're referring to the falsetto part I think you are (during the chorus over the repeated "One Foot Boy"s,) that will be a challenge indeed.
However I think a clue would be that Mika's music is generally by-the-book classical, (music-theory-wise,) and since the end of "One Foot Boy" is a standard choral canon, what he's singing there is very likely a slower (albeit higher pitched) lyric, refrained from elsewhere in the song.
I'll try to figure it out!