This episode dates the series as taking place at some point in the late 5th or early 6th millennium. This is evidenced by Harper describing the Bell X-1, the first human flight module to break the speed of sound, as "going back three millennia, 1947, old Earth calendar, to be exact."
With Harper (Gordon Michael Woolvett), there's lots of humour thrown into his manic, word-stream, full of references, and innuendos, and more (all in good fun). They're typically spoken so fast, that often-times, you're laughing, but nor exactly sure why, or what he said, for that matter. In this episode one of those 'typically Harper' lines, which would sound, 'typically' Harper, is actually said by Rommie (Lexa Doig) to Harper. After Rommie finds Harper building ...something (though, at that moment, he's not actually sure what it is. It's the Bell X-1), Harper (who's extremely manic - much more-so than his usual self, is speaking in various foreign languages; Irish (Galic), French, then Persied. At this point Rommie says, a cunning linguist'. Cunning linguist is used typically in humourously indecent puns, and it's a homophone for cunnilingus. By the way, Harper's reply? 'I speak in all tongues, baby'.