How many countries speak Mandarin Chinese?

It's not accurate to say that a country "speaks" a language. A country is a geographical entity, while language is spoken by its people.

Instead of asking how many countries speak Mandarin Chinese, it's more accurate to ask:

* How many countries have Mandarin Chinese as an official language? The answer is 1: The People's Republic of China.

* How many countries have Mandarin Chinese as a major language? This is a more complex question, as "major language" is subjective. It depends on factors like the number of speakers, the language's role in education, government, and media, and the language's perceived influence.

* How many countries have a significant number of Mandarin Chinese speakers? This is another way to approach the question. Many countries, particularly in Southeast Asia and North America, have large populations of Mandarin Chinese speakers.

So, while Mandarin Chinese is the official language of only one country, it's spoken by millions of people in many others.