Dutch courage, English rose, Irishman's hurricane, Spanish fly. Apart from being nationality adjective-plus-noun compounds, what these terms have in common is that their meanings are not readily retrievable. Neither the words in isolation, nor combined, guarantee comprehension. We can know what "Dutch" and "courage" mean and yet be no closer to "Dutch courage".
Once, no doubt, there must've been a story that propelled "Dutch courage" into the language. And the story must've been known to the users of the language. Alas, it's since dropped off planet English; all that remains is the expression. Today, finding the meaning requires a dictionary or a strongly inferential approach to context. The story is, by and large, gone.
Another example. The expression "gets my goat" (irritates, annoys) allegedly originated in early 20th century America, alluding to the practice of soothing a horse-in-training by placing a goat in its stall. If you wanted a horse to lose a race, apparently you'd quietly take the goat away. I didn't know goats could do that, but there you are.
Today we have the expression but we've lost the story. We could deem this a grievous loss. We could see language as a cemetery of lost stories - and risk being labelled romantic or melancholic. Yet, I was struck by this perspective on language recently as I listened to a young, talented teacher talking about how he introduced the notion of idiom to his class of overseas learners. The expression at work was "the straw that breaks the camel's back".
Gradually and graphically, he established his camel's credentials, adding loads of various weights, one by one, to his archetypal beast of burden. He was almost finished. The load was heavy. The camel, in its species-specific spirit of valiant stoicism, coped nonetheless. Then one straw was added. Camel collapsed. Post-mortem revealed broken back. Culprit? - the straw, of course.
The philosophical implications alone are massive. What caused the back to break? The straw? Or the burden that preceded the straw? Its application to life is endless. How much terrorism do you take before the final (September 11) straw?
Other languages/cultures have the concept, although differently expressed - sometimes, it's a horse or donkey, or the last drop that makes the cup run over. The stories vary, and they're mostly lost.
If we take the cemetery view, we might have radical outcomes. Imagine jettisoning 3-unit maths and 2-unit economics. Substitute cultural literacy. The language would serve as textbook, lost stories as curriculum. Academic success and IT graduates would stop appearing in the same sentence.
But back to reality. An alternative approach is to look to a semiotic explanation. Reframed thus, we might see "Dutch courage", "Spanish fly" and such expressions as signs that have drifted away from their original moorings yet have somehow, miraculously, maintained their original (or similar) signification. This would apply to other opaque expressions. To pursue the Dutch connection, for no particular reason, there's a "Dutch auction", a "Dutch cap", "to go Dutch", "to be in Dutch with", "... or I'm a Dutchman".
In each case, think of the expression as having slipped its mooring and floated away. Perhaps these expressions are like rowboats. Despite the fact that they've been transported far from the seaside where they may have started out, to a remote estuarine fate, they still float and they still function. Perhaps if you want to retrieve the distilled wisdom of ages, you have to chase these expressions, like holy grails, and be rewarded, finally, for your efforts.
But equally, for many who use such boats, it's unimportant where they come from or what the coast was like back there. They float. They serve. Be happy.
Maybe the rowboat is to the cemetery what the bagel is to the hole or the full glass is to the empty.