Shouldn’t Schlauch and schlau be related? And indeed it turns out that, as unlikely as it first seems, according to Duden online, both der Schlauch – “the hose” – and schlau – “smart” or “shrewd” – are related to schlüpfen – “to slip” or “to hatch” or “to emerge.” The specific forms appear have different origins, however. Der Schlauch comes from Middle High German and is related to die Hülle – which seems to make the most sense translated as “the hull” or “the shell” – and schlau comes from Low German and is related to schleichend – the past participle of “to prowl” or “to slink” or “to crawl” and also, as an adjective, “insidious.” Who knows, this latter relationship might have a role to play in the phrase auf leisen Sohlen schleichend – “sure-footed?!”