German orthography
Compound words, including nouns, are written together, e.g. "Haustür" (Haus+Tür; house door), "Tischlampe" (Tisch+Lampe; table lamp), "Kaltwasserhahn" (Kalt+Wasser+Hahn; cold water tap/faucet). This can lead to long words: the longest word in regular use, "Rechtsschutzversicherungsgesellschaften" ("legal protection insurance companies"), consists of 39 letters; while the longest German word ever published ("Donaudampfschiffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft", "Association for subordinate officials of the head office management of the Danube steamboat electrical services") has 79 letters.
Jacob Wackernagel
Another law named after him (Wackernagel 1889) is Wackernagel's law of lengthening ("Dehnungsgesetz" in German), also sometimes known as the law of lengthening in composition ("Regelung der Dehnung in der Zusammensetzung"): in some compound words in Greek the first ingredient ends with a vowel and the second ingredient begins with a vowel; when "neither vowel is high" the first vowel is without effect and the second is replaced by its long counterpart.