The Lekhitic reference article from the English Wikipedia on 24-Apr-2004
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Lekhitic

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The Lekhitic languages (also Lechitic) are a subgroup of the West Slavic branch of Slavic languages associated with the territory of Poland, including Polish, Kashubian, and the extinct Slovincian and Polabian.

The name derives from the old German name for Poland: "Lechien", from "lach", "lech" -- Pole (Polish national).