In linguistics, a hypothetical grouping of languages supposed to be genetically related, but at such a remove of time that this can not be agreed upon.

If the relationship was clear enough that linguists could agree to it, the grouping would be called a family. Established families include Indo-European, Sino-Tibetan, Afro-Asiatic, and Austronesian. The extinct ancestors of these can be reconstructed with some confidence.

Phyla are composed of a number of families, and possibly individual languages that can't be grouped into families. However, it is usually difficult to agree which families can be grouped together. (If it was easy, then the resemblance would be close enough to confirm that they were a single family.) Phyla represent theories rather than facts, and they are usually minority views.

Some that have been proposed are

The term macrofamily is also used. This seems to be a theoretical grouping more firmly based than a phylum but not as definite as a family.