An Etymological Dictionary of the German Language/Annotated/laden
laden (1.), verb, ‘to load, charge, burden,’ from the equivalent Middle High German laden, Old High German ladan (earlier hladan); corresponding to Gothic hlaþan, Anglo-Saxon hladan, English to lade. The d of the Anglo-Saxon word compared with the þ of the Gothic and d of the High German is abnormal; the irregularity is probably on the side of the Gothic and Old High German, which produced a grammatical change as though the Aryan dental were t. In fact, however, it is dh (hladan, hlôd, hlôdum, hladans, not hlaþan, hlôþ, hlôdum, hladans); compare Old Slovenian kladą (klasti), ‘to lay,’ which, with English to lade, proves the existence of an Aryan root kladh. Compare Last and Lade.
laden (2.), verb, ‘to summon, invite,’ from the equivalent Middle High German laden, Old High German ladôn; distinguished from laden (1) by the initial sound; laden, ‘onerare,’ had originally initial hl, while laden, ‘invitare,’ has always had a simple l only; Gothic laþôn, ‘to summon,’ Anglo-Saxon laþian (obsolete in English). The Teutonic root is laþ, the meaning of which is indicated by Gothic laþôns, feminine, ‘calling, consolation, redemption,’ the adverb laþaleikô, ‘very willingly,’ and Modern High German Luder. Some such idea as ‘to treat affectionately, beg,’ must be regarded as the original sense; a root lat with this meaning has not yet been found in the other Aryan languages. Further, the word cannot possibly be connected with Greek καλεῖν, κλη-τός, &c., to which Modern High German holen more probably belongs.