| Term | Definition |
| ariculture theory | The theory that states that agriculture dispersed language. |
| Amerind | The oldest, largest and most widely distributed family. |
| Austronesian | Spoken by people in Taiwan and the Philippines. |
| conquest theory | The theory that states that when people were overpowered by armies, they were forced to accept their language. |
| deep reconstruction | When you re-create a language. |
| Eskimo-Aleut | The last language family to arrive in North America. |
| Fijian | Spoken in Fiji. |
| language convergence | When long-isolated languages make contact. |
| language replacement | When a language is replaced by another. |
| language divergence | The differentiation of languages over time and space. |
| Malayo-Polynesian | Spoken by people in Madagascar and the islands of Melanesia and Micronesia. |
| Na-Dene | The next oldest, next largest, but much less widely diffused family. |
| Nostratic | A pre-Proto-Indo-European language. |
| Polynesian | Spoken by people in New Zealand. |
| (Proto)Indo-European language | The predecessor of Latin, Greek, and Sanskrit. |
| sound shifts | A technique of backward reconstruction. |