Hi, I'm back. Thanks for your patience, and for the amusement. And no, it's not New York (Chinese), not Michigan (Hmong!), not Connecticut (Portuguese), not Alaska (“Aleut/Eskimo” they say – really a language family, not a single language--), and not Nebraska (Nepali – who would have guessed that!).
But Kentucky is right. Good sleuthing, Miss Anthropy!
That leaves just one more state in the US, not yet guessed, where German is the third most commonly spoken language at home. And, to summarize, it is not Alaska, Arizona, California, Connecticut, Florida, Illinois, Iowa, Kansas, Maine, Maryland, Massachusetts, Michigan, Nebraska, New Jersey, New York, Oregon, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, or Wisconsin...