But I think I hear your question. You wonder how a student's ideas (written into a forum or journal) might match words that are stored in an out-of-sight glossary?
I believe the process is the same as those people in this forum who write their posts, save them, and while reviewing for edits, recognize that there is a glossary link available to them.
True, the author might not have chosen "the right words" that trigger such a connection, but that is ok. I never intend for Moodle to make the primary connections between ideas (that's why classmates respond to each other and why the teacher stays involved).
But, for certain, more secondary connections are happening in Moodle because of forums and glossaries then on any student's pad of paper.
Another good activity is to have students regularly rate the various glossary definitions. 1) it helps the writer become clearer; and 2) it gets the class thinking about whether the concepts in the glossary adequately "cover" the ideas posed in the class. This activity increases the chances that a student will adopt some of the terminology used by others in the course.
-Tom