Indo-European languages are a family of languages spoken across Europe and Asia. The existence of this language family was demonstrated by 19th-century comparative philologists, who systematically compared languages’ sound systems, grammatical structures, and vocabularies. These languages share some vocabulary and grammatical affixes, with sounds related through phonetic rules.
The Indo-European family includes major groups such as Indo-Iranian, Germanic, Italic, and Balto-Slavic. Examples of Indo-European languages include Hindi, Persian, English, German, Spanish, Russian, and Greek. Proto-Indo-European, the reconstructed parent language, is believed to have had features such as a non-ergative case system and flexible word order.