It should support a few template sentences which define a word, which is then allowed to occur in the remainder of the text.

More useful than a document which uses only 1000 common words is a document which uses only 1000 words, plus words which it clearly defines.

I feel as if I could write almost anything if I have that, and it will be self-contained and accessible to anyone with the thousand word vocabulary, plus the ability to internalize definitions, which is a very basic faculty of the intellect.