If this interests you, there is an entire hobby that consists of inventing constructed languages. For example, check out this guy's web page, featuring a lot of languages he personally constructed, each with really creative grammar, phonology, and writing systems: <a href="http://dedalvs.conlang.org/" rel="nofollow">http://dedalvs.conlang.org/</a> That guy is so talented that the makers of the HBO series "Game of Thrones" hired him to create the "Dothraki" language used in that show. (I think James Cameron also hired a linguist to create the alien language in Avatar).<p>I will avoid getting into a debate about whether replacing phonemes with other phonemes really makes a new language. But I will say that taking English and coming up with replacements for English words means that you are locked into an English conceptualization of the world. In English, we have a word, "go," that stands for a huge set of concepts; other languages conceptualize the concept of movement completely differently. <a href="http://www.russianlessons.net/grammar/verbs_motion.php" rel="nofollow">http://www.russianlessons.net/grammar/verbs_motion.php</a> . If you treat creating a conlang as a creative endeavor, somewhere in the creative neighborhood of writing a sci-fi or fantasy novel, then a big part of the creativity comes from these types of decisions.