The Indo-European language family is the most widely spoken in the world, with over 3 billion speakers.

Chinese is a member of the Sino-Tibetan language family.

The Proto-Indo-European language is a hypothetical language from which all Indo-European languages are descended.

The Indo-European language family is characterized by a three-gender system, a four-case system, and a subject-verb-object word order.

Romance, Germanic, and Slavic are all branches of the Indo-European language family.

French, Spanish, and Italian are all Romance languages.

English, German, and Dutch are all Germanic languages.

Russian, Polish, and Czech are all Slavic languages.

Persian, Hindi, and Urdu are all Indo-Iranian languages.

Irish, Scottish Gaelic, and Welsh are all Celtic languages.

Lithuanian, Latvian, and Old Prussian are all Baltic languages.

Albanian, Tosk, and Gheg are all Albanian languages.

Armenian, Eastern Armenian, and Western Armenian are all Armenian languages.

Greek, Modern Greek, and Ancient Greek are all Greek languages.

Tocharian A and Tocharian B are both Tocharian languages.