Relationship to other language families A number of factors make the reconstruction of the Northwest Caucasian proto-language problematic: most roots in Northwest Caucasian languages are monosyllabic, and many are single consonants; the sound changes are often intricate, and the numerous consonants and sibilant contrasts provide further complexity; ablaut was extensive and still plays some part in the modern languages; borrowings between languages of the family were frequent; extensive homophony occurs in the modern languages.
Relationship to other language families A number of factors make the reconstruction of the Northwest Caucasian proto-language problematic most roots in Northwest Caucasian languages are monosyllabic and many are single consonants; the sound changes are often intricate and the numerous consonants and sibilant contrasts provide further complexity; ablaut was extensive and still plays some part in the modern languages; borrowings between languages of the family were frequent; extensive homophony occurs in the modern languages