An Etymological Dictionary of the German Language/Annotated/Latte
Latte, feminine, ‘lath,’ from the equivalent Middle High German late, latte, Old High German latta, feminine; it corresponds to Dutch lat, Anglo-Saxon lœtta (lœþþa?), Middle English laþþe, English lath; a difficult word both grammatically and etymologically. The correspondence of tt in Anglo-Saxon lœtta and Old High German latta is abnormal (Anglo-Saxon tt ought to be High German tz, only Anglo-Saxon þþ corresponds to a High German tt). Unfortunately a corresponding word is wanting both in Scandinavian and Gothic. Yet there is no need to regard the cognates as foreign; since Modern High German Laden is cognate, the Teutonic origin of the word is established. Hence from High German Latte an allied Romance class has been rightly derived — French latte, Italian latta, ‘flat wooden pole.’ To the Teutonic cognates Irish slath (Breton laz), ‘rod, pole,’ from the base slattâ, is primitively akin.