Here's why:
* Number of speakers: Russian has the largest number of native speakers, with around 154 million people worldwide.
* Geographical spread: Russian is spoken in Russia, Belarus, Ukraine, Kazakhstan, and other former Soviet republics.
* Official status: Russian is an official language in several countries, including Russia, Belarus, and Kazakhstan.
While other Slavic languages like Polish, Czech, and Ukrainian have a significant number of speakers, Russian stands out as the most widely spoken.