You can apply for Luxembourg citizenship after five years of permanent residency. Your application must include a certificate of Luxembourgish language proficiency and a Living Together certificate. Language proficiency requirements are not too high: A2 - elementary level for speaking skills and B1 - intermediary level for listening comprehension. The Living Together certificate confirms that you either attended the 24-hours course about rights of citizens, state institutions and national history, or passed the test without attending the course. It takes six to eight months to get a decision on your application.