Answer to Question 1
Answer: Any isolated group of people develops a language of its own. This language describes everything that those people see or experience together. If groups of these people break away and disperse, then each group discovers new objects and ideas, and the people have to make up new words for them. After hundreds of years, the descendants of each of these breakaway groups have their own language. Each descendant language has a vocabulary of its own, but each also retains a common core of words from that earliest shared language. When languages separate, they still have a genetic relationship, meaning they share a common ancestor language. The ancestor that is common to any group of several of today's languages is called a root language, or protolanguage. The languages that are related by descent from a common protolanguage comprise a language family.
Answer to Question 2
Answer: Many factors can affect the diffusion of religious practices. One way is through the process of proselytization, which is trying to convert others to one's religion. This is often the work of missionaries and pilgrims who travel and spread their ideas among others. Many of the world's most important religions proselytize, but some do not. Often, religions are described as either universalizing religions, which seek new adherents through proselytization, or ethnic religions, whose adherents are typically born to a particular cultural group. Historically, many governments have designated a national or established church that is the official religion. This helps to spread a religion, often with funding from the government.