Which Constitutional Article empowers the State Legislature to adopt Hindi or any state language as the official language of that state?

Article 345 of the Constitution empowers state legislatures to adopt any one or more of the languages in use in the state, or Hindi, as the official language of that state. This federal provision allows states to choose their official language based on local linguistic preferences. Article 346 deals with inter-state communication, Article 348 with language in Supreme Court and High Courts, and Article 349 with special procedure for language use during transitional period.