Donaudampfschiffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft
Donaudampfschiffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft is a compound word that serves as an example of the virtually unlimited compounding of nouns that is possible in many Germanic languages. According to the 1996 "Guinness Book of World Records", it is the longest word published in the German language.
...ish (audio drama)
The Omniverbum is the mythical longest word in existence. According to records, no one who has found the Omniverbum, or its sentient affix "Ish", has lived to tell of it. Except one. Book found the Ish on an obscure world and accidentally brought back to the college as per his programming. But now it's escaped, and is out to cause havoc on the speech centers of the human brain unless The Doctor can stop it.