Um, Rhet, can't you just change the gloss-generating script to produce
<span class="gloss_p">
<b>Fremdsprache</b>
<span class="gloss">foreign-language</span>
</span>
from
[g foreign-language]Fremdsprache[/g] (alternatively, do some CSS magic)? Or would you like to keep the ability to bold individual words?