It has a membership of about 150 languages, including most European languages and Indian Subcontinental languages. It is the first and most widely investigated language family of the world.

• 印欧语系锁骨历史语言学家研究最早和最深的一种语系。印欧语系含大部分欧洲语言和印度次大陆语言在内的约150种语言。