The cream of the Germanic summer: butterfly, Schmetterling, vlinder, sommerfugl, fjäril, fiðrildi
At this point, the less dedicated etymologist might start to falter, and perhaps close the folder. The more dedicated etymologist may pause to consider that the flight of a butterfly seems faltering, that a butterfly flaps its flat wings like a folder, and that the older, more staid German name for ‘butterfly’ is Falter, which also means ‘folder’.
But they didn’t name the butterfly after a folder… well, not entirely. Falter as in ‘folder’ comes from falten, which traces to an entirely different Proto-Germanic root than Falter as in ‘butterfly’. The pretty bug Falter traces back to… the exact same Indo-European reduplicated *pal- as Latin papilio. It came into Proto-Germanic as *fifaldǭ, which almost has the same soft sound as butterfly flaps, except really you can’t hear butterfly flaps, can you. That got fancifully altered into different versions such as Zweifalter, and was backformed to Falter, perhaps under the influence of the other Falter. But then Germans decided that they preferred the idea that this ostentatious insect had something to do with cream and called it Schmetterling instead, from Schmetten, an Austrian word for ‘cream’ (more commonly called Sahne or, especially in compounds, Rahm).
But that *fifaldǭ root didn’t just flap away. It fluttered into Old Norse, where they got the idea that it had something to do with feathers (fiðri) and “corrected” it to fiðrildi, which is also the modern Icelandic word. And fiðrildi, in turn, got left in someone’s pocket and went through the wash and came out as Swedish fjäril.
And maybe, just maybe, fifaldǭ somehow became Dutch vlinder and the now-disused English flinder. If it did, we can’t say how it got that way. Really it’s too hard to follow and it didn’t leave enough traces. But while the Dutch accepted vlinder and kept it, the English decided instead that they would prefer to name the bug after butter.
I mean, OK, German cream, English butter, why the heck not. But why the heck? Why are overdressed insects associated with fatty dairy products? Some people speculate that it’s because one particular butterfly is yellow like butter. And OK, if that’s a dominant kind of butterfly in England (sort of like how eggplant got named eggplant because the people who named it that knew just the white kind), but is it? Others speculate that it’s because it came out in summer butter season, or because it was thought to steal butter, or something like that. What we do know is that there have been assorted similar names for it in Dutch and German meaning not just ‘butter fly’ but things like ‘butter witch’, ‘butter bird’, and ‘butter wife’ – plus the Dutch boterschijte, ‘butter shit’ (are Dutch butterflies especially vexatious? or are the Dutch particularly put out by fancy little flighty things?). But we don’t know how this all started; whoever could have recorded its origins clearly had butter things to do. So it might as well be random.
And then there’s Danish. And Norwegian – the modern kind. They could also have had a descendant of *fifaldǭ. But they don’t. Instead, they liked the version confected by someone back in the Hanseatic period (or thereabouts – starting about the 13th century): ‘summer bird’ – Middle Low German somervogel (compare Yiddish zumer-feygele, not the most common Yiddish word for ‘butterfly’ but it exists), which became Danish and Norwegian sommerfugl. And why the heck not. Summer is short but pretty in Scandinavia, just like the life of a butterfly.