When you are interpreting (or translating, but to a lesser degree), you will learn a lot of words on the fly by hearing your client use them. These words will likely come up again in subsequent sessions. You know you will need them so you jot them down on the edge of your notebook. But you end up with a long list of words that you never then up studying. If you are like me, this is frustrating. I have hundreds of little slips of paper with words from meetings I can’t even remember. You know you need to learn these words but you don’t have time and end up “learning” them all over again the next time someone uses them in a meeting.
My advice to you is simple. Make time. As an interpreter who was not born speaking both languages, you have a duty to continue learning. So, you have to make time to improve your weaknesses (vocabulary being one of the major ones). Try this: the next time you are going into a meeting or presentation where you know the same things are going to be discussed, take 15 minutes to review the vocab notes from the last time. You will be glad you did.