Learn Spanish (Spain): ¿Os gusta la cerveza?

In Spanish, the verb gustar works differently than the English verb 'to like'. It actually means 'to be pleasing to'. So, this sentence translates more closely to 'Is beer pleasing to you guys?'. Because la cerveza (the beer) is the single thing doing the pleasing, the verb matches it and takes the singular form gusta.

What does the word os do in this sentence?

Os means 'to you all' or 'to you guys' in Spain. It tells us who the beer is pleasing to. It is the pronoun used to match vosotros (the informal plural 'you' used in Spain).

Why is there a la before cerveza? In English we just say 'Do you like beer?', not 'the beer'.

When talking about things you like, dislike, or talk about in a general sense, Spanish requires a definite article (el, la, los, or las). Because of this rule, you must include la before cerveza even though we skip the word 'the' in English.

If the speaker was asking about multiple things, how would this sentence change?

If you are asking if someone likes plural things, the verb changes to match the plural subject doing the pleasing. You would use gustan instead of gusta. For example, to ask 'Do you guys like the beers?', you would say ¿Os gustan las cervezas?.