Comment Simplified Technical English (Score 1) 626
English being a de facto international language, as has been thoroughly pointed out, might be something to start with. Simplified Technical English, http://en.wikipedia.org/wiki/S..., is used by various government agencies to remove some of the ambiguity of English. While it and similar efforts may or may not be sufficient as an everyday language, it is an idea to consider.
You should also include these sites as a source of ideas and to see some of what has already been done, http://conlang.org/, http://omniglot.com/