Conlangs DE-Cal: A class on constructing languages at the University of California Berkeley.
Constructed Languages: Links to many conlang sites as well as the author's own conlang.
Constructed Languages: An encyclopedia entry describing constructed languages, including sections on auxiliary languages, artistic languages, and logical languages.
Phonetic Picture-Writing: Phonetic picture-writing can also be read phonetically. Its ideograms are composed of special letters. Authored by Leonhard Heinzmann.
Studoj pri Interlingvistiko / Studien zur Interlinguistik: Journal article by Wim Jansen that reviews a book on language planning and language policy by Sabine Fiedler and Liu Haitao. The book is on the theoretical and applicational aspects of interlinguistics, esperantology, terminology and lexicography.
Universal Language Dictionary Project: An attempt to create a list of concepts, described in English, along with words to express those concepts in several natural and artificial languages.