WHY DOES GLOSA HAVE THREE LEVELS OF VOCABULARY?
The GLOSA 1000, 2000, and 6000 thing is what really makes Glosa stand out. If you're going to "plan" or construct a language, why not give it different levels of vocabulary-- a very small one for beginners or for emergency situations when there isn't much time to learn a vocabulary, and a larger vocabulary for those with more literary, legal, or technical interests?
GLOSA 1000 always had more than 1000 words, partly because of duplicates from Latin and Greek; for example, Latin AQA and Greek HIDRO both mean "water," and both are often used in technological terms. Furthermore, the idea of GLOSA 1000 also included all the names from scientific taxonomy for animals, plants, and elements of the periodic table. GLOSA 6000 was written for those desiring a larger vocabulary. Technically any word root derived from a modern technical or scientific word can be used as a Glosa word.
Wendy Ashby has been working on getting Glosa's different vocabularies more organized. What used to be called GLOSA 1000 now is called "Core" or "Central" Glosa. It has about 1300 words. If you feel you need a slightly larger vocabulary, use "Basic" Glosa. These are marked in the Glosa Internet Dictionary (GID) at _www.glosa.org_. There are plenty of other words there if you need more.
In my own writings, I use mainly Central Glosa and have found it quite versatile. I do sometimes borrow a word or two from Basic Glosa, and I rarely need anything beyond this.
Don't be afraid to write things like, "Written in Central Glosa," or, "The following text is in Basic Glosa," at the beginning of your work.