Learn Portuguese (Portugal): Diz-se muita coisa nesta vila. - People say a lot of things in this town.

The -se added to the verb creates an impersonal meaning. Literally, it translates to "It is said" or "One says". In natural English, we usually express this general statement as "People say" or "They say".

Why is muita coisa singular if the English translation says "a lot of things"?

In Portuguese, it is very common and idiomatic to use the singular phrase muita coisa (literally "much thing") to refer to "a lot of things". You could technically say muitas coisas, but muita coisa sounds much more natural to native speakers in this context.

Why does the pronoun come after the verb in Diz-se? Could I say Se diz instead?

In European Portuguese, you cannot start a sentence with an attached pronoun. Because the verb is the very first word in the sentence, the pronoun must attach to the end of it with a hyphen. Saying Se diz at the start of a sentence is a Brazilian Portuguese trait.

How does a vila differ from a cidade?

A vila is a town, whereas a cidade is a city. A vila is generally smaller and less populated than a cidade, but larger than an aldeia (a village).