William Lloyd Welden, known as Bill Welden, is a linguist, seminal contributor to Parma Eldalamberon, and part of the editorial team for the international Elvish Linguistic Fellowship. He hosted their first symposium ("ELFcon"), of four, in 1991. Specializing in the languages of J.R.R. Tolkien's mythology, Welden has written many articles for Parma Eldalamberon, the journal Vinyar Tengwar for which he is a board member, and the Tolkien Society's formal linguistics journal Quettar. Some of these are co-written with Christopher Gilson.
In the 1990's, he joined the team of Carl F. Hostetter, Arden R. Smith, and others to assess and edit J.R.R. Tolkien's unpublished material on his invented languages.
His commentary on Tolkien's development of Middle-earth's history is found in Michael Pellerin's J.R.R. Tolkien: The Legacy of Middle-earth, found in the Extended Edition of Peter Jackson's The Return of the King film.
Since 2005[1], Welden has organized the biennial Omentielva gatherings, the "International Conferences of J.R.R. Tolkien's Invented Languages", held across Europe.