Conlang stands for Constructed Language. Basically it means a made up language, like Quenya (Tolkien's elvish) or Esperanto. It's not just a transliteration of English, or a replacement of English words with weird sounds. A conlang is a full blown language with it's own vocabulary, grammar, syntax, phonology, quirks and everything. If you search around the net you'll find all sorts of resources devoted the hobby. Some conlangs are meant to work like real languages and others try to push the limits of natural language in various ways. For me it's a yet another quirky hobby. Even if learning a new language intimidates you I recommend checking out some of the conlangs bellow; you might be surprised how fun playing with language can be.