Russian and English are common second languages in the country. Russian was taught to everyone under Soviet rule and is still commonly understood by the older generation who grew up under Soviet rule. English is slowly becoming the most popular second language in the country as it is commonly taught in schools and most of the country's younger generation learns and speaks this language to varying degrees.
Religion
Nearly every Azerbaijani is Muslim, while some minority ethnic groups (Russians and Armenians) are Christian, although these people make up a very small percentage of the people. Perhaps due to the Soviet's atheist rule, few Azerbaijanis are practicing.
Islam (the name of the religion, whose followers are called Muslims) is a monotheistic religion, whose holy book is called the Qur'an. The Qur'an is believed to be the word of God spoken through the prophet Muhammad from 609-632 CE (Common Era is preferred over AD (Anno Domini or "year of the Lord") since the Islamic world doesn't believe Jesus was the messiah). Islam believes Muhammad was the last prophet sent to earth by God, the last in a long line of prophets, which includes Moses, Abraham, and Jesus among others.
Muslims follow five pillars of their faith: testimony, prayer, alms-giving, fasting, and pilgrimage. These pillars, and other tenants of their faith, can give great structure to their lives as some foods, like pork, are forbidden and every Muslim is expected to pray five times a day. However, the level of participation in each of these pillars and to what degree Islam influences an individual's life varies from person to person and community to community. Generally speaking, Azerbaijan is very liberal in how they practice Islam.