Many times when someone finds out that you know a language other than English they'll ask you to say something in that language. Some people I know will do just that and say whatever "something" is in their language. It's a simple answer and avoids you having to think of a random sentence to say. And if you ask them, "What do you want me to say?" then they'll usually think of the most convoluted complex jargon for you to translate. When you can't translate it they'll say, "I thought you said you knew language x?" So instead of having to deal with all that, just say today's word of the day, "something", or in Arabic, شي.
Examples for context:
1. مشينا شي 20 متر (mshayna shi 'ashreen mitr) - We walked about 20 meters.
2. ما بدي شي منك (ma beddi shi minnak) - I don't want anything from you.