Gothic (E. Germanic, Indo-European), Siroi and Kewa (Trans-New Guinea), Dizi (W. Omotic, Afro-Asiatic; but see Counterexamples to #567 for a caveat), Akkadian, Eastern Libyan Arabic (both Semitic, Afro-Asiatic), maybe also Chamorro (Chamorro, Western Malayo-Polynesian) and Hupa (Athabaskan) (Plank 1989: 299 ).
Plank 1989: 299-301, proposes to change the conjunction of the implicatum to a disjunction in order to avoid the counterexamples mentioned above: The dual does not extend to non-pronominal noun-phrase-internal agreement unless it extends to nouns. The dual does not extend to non-pronominal noun-phrase-external agreement unless it extends to personal pronouns.There is a natural diachronic reading of “extend” in this implication, and in many others of that kind.
Plank 1989: 299-301, proposes to change the conjunction of the implicatum to a disjunction in order to avoid the counterexamples mentioned above: The dual does not extend to non-pronominal noun-phrase-internal agreement unless it extends to nouns. The dual does not extend to non-pronominal noun-phrase-external agreement unless it extends to personal pronouns.There is a natural diachronic reading of “extend” in this implication, and in many others of that kind.