Switzerland has four official languages: German (spoken by 64%), French (20%), Italian (6.5%) and Romansh (0.5%). Zurich lies in the German speaking part of the country, where people speak a German dialect, so called Swiss German or Schwyzerdütsch, which differs from region to region. Be it among friends, at work or when dealing with the authorities, people speak dialect. For anyone who speaks or - even worse - is learning to speak German, this can be tiring because at first it‘s very hard to understand even for people with a German mother tongue.
However, Swiss people use standard German, so-called Hochdeutsch, when writing and speaking at school and so do the presenters on TV. When Swiss realise you are a foreigner they will usually switch to standard German. Keep in mind that a lot of Swiss aren't practised in standard German - it‘s like a foreign language to them too. Occasionally German speakers from outside Switzerland claim they have no trouble understanding the dialect – but most of the time the Swiss they were speaking to were actually trying their best to speak standard German.
A lot of Swiss speak English fairly well, especially the younger generation. So generally getting by in English is no problem. Often the first foreign language at school is still French, so if you happen to speak some you can try to use it, especially with elderly people who don‘t speak English. As Italian is the country‘s third language, people with a higher education usually speak some Italian as well.
Here are a few German phrases and some typical Swiss German words - it will be always appreciated if you use a few Swiss words. The 'r‘ in Swiss German is rolled, the ‘ch’ is pronounced like in the Scottish loch. Mind your throat.
Swiss German Grüezi (groo-e-tsi) Hello (formal) Adieu (as in French) Goodbye (formal) Merci (mersi) or Danke Thank you