It may be a last resort to some people, but hand gestures and miming go a long way towards getting your point across. Looking like a bit of a fool for a few seconds may save you a lot of time spent searching for vocabulary. And you may not even look so silly; many people are ‘hand talkers’ and use gestures to go along with everyday speech.
Especially when you’re a beginner, and in a foreign country, gesturing and pointing can be a great help when you don’t know specific vocabulary. I did have a friend who had to mime some unfortunate bodily functions at a hospital once, but hopefully your experience won’t be as traumatic. If you’re lucky, the person you’re trying to communicate with will provide you with the vocabulary you need (“ah…tomato!”) once they finally understand your meaning.
If you need any other impetus to start moving your hands, this study has shown that gestures, languages and symbols are all processed in the same regions of the brain, and it may be a carry-over from before humans had speech. So, waving your arms around could be considered more valid than speaking. Just remember that some gestures aren’t always polite!