there are a lot of translations open from <-> to languages which are rare. But sometimes there is the source- or the goal-language one of them you knows.
I think it should be to set up a "transit-language" without subtraction of points if request e.g. is older than a month. When someone set-up an "transit-language" the requestor would be asked, if he accept the setup. If accepted by requestor, the points will be substracted from his account and the person, who's setted up the inter-language-request shall receive an info and do this translation. Timeout for this: e.g. one week...