As I have already written about inverted commas in Spanish language, I think it is a good idea to know how they are used in English writing.
They are called quotation marks or quotes in American English, and inverted commas in British English. British writers use both single (‘ ‘) and double (” “) inverted commas, but American writers tend to use double inverted commas (” “).
The ones used to begin a quote are called opening inverted commas, and the ones used to end a quote are called closing inverted commas.
You put them at the beginning and end of direct speech:
“No problem”, I said.
Note that you start the direct speech with a capital letter.
In American English the punctuation is put in front of the closing inverted comma, not after it:
I couldn’t believe it when she called them “sad and lonely people.”
You do not give the first word of the continuation a capital letter, unless it would have one anyway. If you are giving more than one paragraph of direct speech, you put inverted commas at the beginning of each paragraph but not at the end of any paragraph except the last one.
The hierarchy of the inverted commas in English depends on the ones you use first: if you are quoting someone who is also quoting, you need to use a second set of them for the second quote; usually the inverted commas you haven’t use for the first quote, for instance:
‘What do you mean,’ she said, ‘by a “family trouble”?’
The same way as in Spanish, inverted commas are put round a word or expression which can be inappropriate:
Her dress was ruined when a “friend” jokingly poured a bottle of wine over it.