Julius Moormann (1889-1974) was born in Goor and worked as a teacher of Dutch and as high school principal in Maastricht and Nijmegen. From childhood, he had great interest in language, most notably in slang and 'secret languages', as he would call the languages of thieves, cattle dealers and peddlers.

He published many articles about the fieldwork that he did on his bicycle during school vacations. His dissertation on secret languages appeared as a trade edition in 1932, and a second volume appeared in 1934. His work was reprinted in 2002 along with a third volume he had left behind, titled: The secret languages: The standard work on slang, with a new section added on. Besides the collections of broadside ballads published by him and Wouters, he also published various articles on songs.

Just like Wouters, Moormann collected a great deal of source material on broadside ballads. After his death, this all ended up at the Meertens Institute in Amsterdam.

During the Second World War, Moormann made himself useful to the resistance, for which he received numerous decorations. He retired in 1954, and died in 1974.