What 3 countries speak mandarin?

It's a bit tricky to say "speak Mandarin" as it implies that it's the only language spoken in a country, which isn't true.

However, Mandarin is the official language in these 3 countries:

1. China: This is where Mandarin originated and has the largest population of Mandarin speakers.

2. Singapore: Mandarin is one of four official languages in Singapore.

3. Taiwan: Mandarin is the official language of Taiwan, though there are also other dialects spoken.

It's important to remember that while these are the countries where Mandarin is official, there are many other countries and regions where Mandarin is spoken, either as a second language or by significant communities.