This is the first article in a series on language and culture. Although more than 400 million people speak English as their first language, they have their own expressions and words unique to their culture. In fact, communication is more than just speaking. We all learn how to use glances, gestures, changes in our tone of voice and other non-verbal cues to get our message across. Yet how we use them depends on where we live. Let's take a look at some of the differences. What does it mean when you nod your head? In Britain, it means 'yes', in Japan it means 'I'm listening' and in Bulgaria it means 'no'. A country's unwritten rules of communication can be baffling to an outsider, but being aware of the differences is the first step to understanding them. Space Striking up a conversation in a lift might go down well in the US, but it'll arouse suspicion in Britain. Every culture has rules about personal space - the invisible space between you and another person. In Indonesia, it's not uncommon to see men walking arm in arm, while in Britain, only men and women do this. In Greece and Italy, hugs and kisses among friends are expected, but some Chinese and Indians get touchy if you get too close. The key to respecting personal space is to follow the cues: back off if someone backs away. Body language The eyes, hands, feet and mouth - our bodies communicate as much as our words do. But people from different cultures don't always see eye to eye on the subject of 'body talk'. For example, in Britain, looking someone in the eye is a sign of honesty, while in Japan, it's considered to be disrespectful. Pointing the soles of your feet at someone is also insulting to the Japanese because the feet are thought to be dirty. And when it comes to cross-cultural gestures, things can really get out of hand. For example, a 'thumbs-up' sign is positive in the United States, but it's impolite in Bangladesh. Yet there is one thing that's universal - a smile. Voice It's not what you say, it's how you say it. A Briton who hears two Italians talking loudly might think that they're arguing; but in Italy, speaking loudly and interrupting the other person can be a sign that you're really involved in the conversation. Conversation is important in all cultures, but how you participate varies from place to place. In North America, it's important to show you're listening by nodding your head and making noises like 'uh huh'. Yet in some Asian countries, people show they're listening by keeping still and remaining silent, which can be awkward to people from English-speaking countries. So the next time you're in a foreign country, look and listen before you speak. Time In Britain and the US, people value punctuality. If you agree to meet friends at 7pm, you can bet they'll arrive on time or shortly after. But if you're meeting someone from India or Brazil, you'll have to wait a while. Notions of time vary around the world, so it's a good idea to find out about time-keeping habits in the country you're visiting before you arrange to meet someone. Cross-cultural communication can be tricky when you don't know the rules. But it's not impossible. The first step is to recognise that there are differences; the next step is to respect them. You could start by making a list of cultural dos and don'ts around the world.