Linguists (people who study languages)  have often used trees and branches as metaphors to explain and map the connections between language groups. This linguistic family tree shows how these languages grew from a common root. It also demonstrates how languages can evolve and branch out over time. The European arm of the tree splits off into Slavic, Romance and Germanic branches. The size of the leaves on the trees is intended to show  how many people speak each language. The larger the leaves, the more speakers of that language. The closer together the languages are, the larger the connection between them. For example, English and German are on different branches, but are still closely related.