I see 2 problems with the autotranslate:

1. Very limited number of words. As you say this is a limit of the system, then you need to improve this system. This is not 1980. This is 2015 and an Input Method on the PC easily handles tens of thousands of entries in just one language. All it means is that you designed the system to have a very limited capacity. "We're not going to need that many entries anyway." This is something that can and should be improved if you ever want to make the auto-translate more than a pair of pretty curly brackets that sometimes pop up in the chat.

2. Very limited matching ability. It only matches from the first letter/word and doesn't do partial matches. Typing "blade" and activating auto-translate will not match "Savage Blade", "Fast Blade", "Riot Blade". That is not intuitive. It effectively means we have know exactly what we are looking for before we can use it, which translates to learning the entries off by heart.

If you could only improve on these two aspects of the system, you make the auto-translate ten times more useful if not more.