Arawakan Vs. Maipuran
Filippo Gilii recognized the unity of the Maipure language of the Orinoco and Moxos of Bolivia in 1783, and named their family Maipure. It was renamed Arawak by Von den Steinen (1886) and Brinten (1891) after one of the most important languages of the family, Arawak in the Guianas. The modern equivalents are Maipurean or Maipuran and Arawak or Arawakan. The term Arawakan is now used in two senses. In South America, Aruák is generally used for the family demonstrated by Gilij and subsequent linguists. In North America, however, it has been extended to a hypothetical proposal that adds the Guajiboan and Arawan families. The name Maipurean was then resurrected to distinguish the core family, though this is sometimes called core Arawak(an) or Arawak(an) proper instead.
Kaufman (1990: 40) relates the following:
name is the one normally applied to what is here called Maipurean. Maipurean used to be thought to be a major subgroup of Arawakan, but all the living Arawakan languages, at least, seem to need to be subgrouped with languages already found within Maipurean as commonly defined. The sorting out of the labels Maipurean and Arawakan will have to await a more sophisticated classification of the languages in question than is possible at the present state of comparative studies.
Read more about this topic: Arawakan Languages