Working with people of differing languages can be a challenge. They don't know your language and you don't know theirs. However, there are some steps/tips that will prove to be very helpful when interacting with them.
Step 1: Identify What You Need to Communicate to the Person
Know what you will need to be communicating to him or her because this determines the amount of language that you will have to know. If it is simply a few directions and/or answering a basic question then you can easily show them what to do without knowing much of the language. Now if it is more than that, you may want to take a look at ways to increase your ability to speak that language.
Step 2: Gain Some Knowledge of Their Language
The best way to effectively communicate with people speaking different languages is to learn it. While it may not be worth it to become fluent in it, if you can thats just for the better. All you really need is to know enough to where you can understand them. Even if it is the most basic of conversations, knowing some is going to be a whole lot more helpful than none.
Step 3: Communicate the Best You Can
It is ok to mispronounce words, have broken sentences or otherwise not have the best knowledge of the language. As long as you are able to get your message across then you have done your part. The other speaker should know that you will make mistakes and otherwise butcher the language because of your limited knowledge of it. If you cannot even make some sort sense when your are talking then you need to go pack to step 2.
Step 4: Make It a Team Effort
If it is necessary for both of you to communicate in order to effectively work then each of you should work to understand each other's language. Both people learning a little about the other language will allow you to have a basic conversation must faster which is all that is needed in most situations*.
*More knowledge of the language may be necessary depending on what needs to be communicated.
Step 5: Continue to Practice the Language
Without constant repetition and practice, you will go nowhere in language. If possible put yourself in a situation that people only speak that language. That is the best way to learn. By only speaking the language your studying, it will become easier and easier to have a conversation.