Although to be sure, a doppelganger is not the kind of identical twin who will finish your sentences for you and let you borrow her clothes.
Seeing your double generally foretells bad things to come.
A word we may not yet have come up with is hausfrau.
Lots of city names in the United States come from German, especially pretty much any city that ends in -berg (which means ‘mountain’) or -burg (which means something like ‘fort’).
There’s also a town in Maine called Berlin. Apparently, somebody missed their hometown a lot…
Norway, Paris, Denmark, Naples, Sweden, Poland, Mexico, China, and Peru, all within a 100-mile radius of Lynchville, Maine.
As others have said, a huge number of English words are of Germanic origin but we have borrowed a surprisingly small number from modern German. Mostly just some food names and a few specialized terms. There would probably be more if not for the stigma the German language picked up in the US thanks to the World Wars, although I know a few of the modern German words we do use were actually brought back by GIs after WWII. “Kaputt”, for instance.
Random anecdote: While looking something else up in my German/English dictionary I saw there was an entry in the English section for “kindergarten”. I thought that was strange, since “kindergarten” is one of the few common English words that has been borrowed directly from German. But sure enough, they had a translation listed there: “Vorschule”.
I then checked “Kindergarten” in the German section and found it translated as “nursery school”. Not being familiar with the German school system I’m not sure what to make of this. Perhaps a German Kindergarten is more like what Americans would call a pre-school, while an American-style kindergarten (a grade in elementary school before the “first” grade) would be called Vorschule in German. But if true this would be especially confusing, as “Vorschule” literally means “before school” or “pre-school”.
While it’s true that lots placenames are German in origin, unfortunately, you can’t count on the -burg ending to indicate it. About a century ago, the US Board on Geographic Names decided to “standardize” US placenames and one of the things they did was decree that places ending -burgh drop the final H. That changed a number of Scottish names to look like they were German.
Most places changed without complaint, although Pittsburgh had a long-running battle about it and finally kept their H. A few other places kept their H (e.g. Newburgh NY) and some restored it later. For example, for a long time, Edinburgh IN was spelled Edinburg. Not sure when they changed back, but apparently sometime in the 90s.
It’s only a small list when compared with borrowings from French, Spanish, Italian. and maybe Dutch. But they exceed those from any other modern European language.
Other WWII era borrowings are Nazi, gestapo, snorkel, panzer, and blitzkreig (later modified to blitz as an American football term). From WWI we got strafe.
Furthermore, there’s quite a few scientific terms, especially from chemistry, minerology, and biology that come from German. Zinc, quartz and gene are examples.
For more, see the thread I linked to earlier and which everyone is ignoring: http://boards.straightdope.com/sdmb/showthread.php?&threadid=62948
Schist, Gneiss, and the -wacke half of graywacke from geology.
Kaffeeklatsch, which Americans have semi-anglicized to coffee klatch and is now probably long obsolete anyway.
And my favorite of all:
Lysergiksäurediethylamid. Better known in English by its abbreviation.
Oh yeah, one more:
Schwanz.