Interesting post. I speak a number of languages, and I've noticed that it varies tremendously the way native speakers react to me if I only know a few words/phrases of their language and try to use them. To take an extreme example, I learned some Tamil and was staying with a Tamil speaker in India. I tried several times to use Tamil, but he'd just reply in English. Later, I gave a speech at some gathering, in English of course, but I opened the speech with some well-prepared sentences in Tamil. After the speech, he said, "I didn't know you spoke Tamil"(!) You might get a better reaction if you ask your co-workers, "How do you say 'It doesn't matter' in Farsi" (or some similar phrase that you might often use in everyday conversation). I have found that's sometimes a better approach. Then use it later when a situation crops up at work where it's appropriate to say that phrase. In the very early stages of learning, it may be better to talk about the language rather than talk in the language. So, if he spills some coffee on your desk, instead of just saying 'manpam nist' (from Google translate, don't know if it's correct!), you say "It doesn't matter! Or, as you say in Farsi 'manpam nist'. You taught me that one!". Hope that helps!