How can I handle angry customers who don't speak my language?

Calm the customer down as the first step to how to handle them, make sure they are comfortable then look for someone who can speak their language

the most important in this case to be patient and double- check customer's understandingshow some empathy and care for customers words and the most important thing to keep your tone stable never shout or underestimate him

Allow them to speak without interrupting.... Once he/she realize that you are not a rude person but instead a calm person, they will give you a chance to express yourself and explain what happened. This will impress the client and promote the company's credibility.

Understand the customer body language. Try to make him cool how? Tell them anything that he will be beneficial with service which is you providing.

listen to the customer try to understand according to his body language  as what he is trying to tell make himself comfortable let him calm down.

Base on personal experience:

1. Primarily, by using positive body language and facial expressions, to show you're approachable and ready to help.
2. Secondarily, by establishing  "Smart" means of communications ASAP by1) Using pen and paper communication a) Images b) Words2) Calling "by phone or in person" someone who does understand the customer

why the customers are getting angry because need a proper support or solution

we need to listen the concern with out interrupting first say sorry once the customer fished his/her concern then give the solution appropriately

if you can give confirmation give anything other wise don't do that

don't loose your confidence and voice modulation   

As said if customer don't speak your language. The gestures and body language will have importance and should reflect what you want to say.

Best Example is Charlie Chaplin, he never speaks but most of them understands.