* Different definitions of "Hindi": Some count all speakers of Indo-Aryan languages (including Urdu) as Hindi speakers, while others focus only on speakers of the standard Hindi language.
* Data collection challenges: Obtaining accurate language data from every country is challenging.
However, here are some estimates:
* Ethnologue: Estimates 602 million Hindi speakers worldwide, making it the fourth most spoken language.
* UNESCO: Estimates 400 million native Hindi speakers and an additional 300 million speakers of other Indo-Aryan languages (mainly Urdu).
Therefore, a reasonable range for total Hindi speakers worldwide could be between 400 million and 600 million.
It's important to remember that these are estimates, and the actual number may vary.