in a Macro-Caucasian (earlier Vasco-Caucasian) family (see the section on Macro-Caucasian below). According to him, it is as yet premature to propose other nodes or subgroupings, but he notes that Sumerian seems to share the same number of isoglosses with the (geographically) western branches as with the eastern ones: 1. Dené–Caucasian 1.1. The Macro-Caucasian family 1.1.1. Basque 1.1.2. North Caucasian 1.1.3. Burushaski 1.2. Sumerian 1.3. Sino-Tibetan 1.4. Yeniseian 1.5. Na-Dené Proposed subbranches Macro-Caucasian John Bengtson (2008) proposes that, within Dené–Caucasian, the Caucasian languages form a branch together with Basque and Burushaski, based on many shared word roots as well as shared grammar such as: the Caucasian plural/collective ending of nouns, which is preserved in many modern Caucasian languages, as well as sometimes fossilized in singular nouns with collective meaning; one of the many Burushaski plural endings for class I and II (masculine and feminine) nouns is . the consonant -, which is inserted between the components of some Basque compound nouns and can be compared to the East Caucasian element - which is inserted between the noun stem and the endings of cases other than the ergative. the presence of compound case endings (agglutinated from the suffixes of two different cases) in all three branches. the case endings themselves: As Bengtson (2008) himself notes, an ergative ending -/s/, which may be compared to the ending that has instrumental function in Basque, occurs in some Sino-Tibetan languages, and the Yeniseian language Ket has an instrumental/comitative in . This suffix may therefore be shared among a larger group, possibly Dené–Caucasian as a whole. On the other hand, comparison of noun morphology among Dené–Caucasian families other than Basque, Burushaski and Caucasian is usually not possible: little morphology can so far be reconstructed for Proto-Sino-Tibetan at all; "Yeniseian has case marking, but it seems to have little in common with the western DC families" except for the abovementioned suffix (Bengtson 2008:footnote 182, emphasis added); and Na-Dené languages usually express case relations as prefixes on the polysynthetic verb. It can therefore not be excluded that some or all of the noun morphology presented here was present in Proto-Dené–Caucasian and lost in Sino-Tibetan, Yeniseian and Na-Dené; in this case it cannot be considered evidence for the Macro-Caucasian hypothesis. That said, as mentioned above, Basque, Caucasian and Burushaski also share words that do not occur in other families. A genitive suffix -/nV/ is also widespread among Nostratic