Macro-Siouan languages
In the 19th century, Robert Latham suggested that the Siouan languages are related to the Caddoan and Iroquoian languages. In 1931, Louis Allen presented the first list of systematic correspondences between a set of 25 lexical items in Siouan and Iroquoian. In the 1960s and 1970s, Wallace Chafe further explored the link between Siouan and Caddoan languages. In the 1990s, Marianne Mithun compared the morphology and syntax of all the three families. At present, the Macro-Siouan hypothesis based on relations among Siouan, Caddoan, and Iroquoian is not universally accepted as proven.
Visayan languages
Native speakers of Visayan languages, especially Cebuano, Hiligaynon and Waray not only refer to their language by their local name, but also by "Bisaya" or "Binisaya", meaning "Visayan language". This is misleading or may lead to confusion as different languages may be called "Bisaya" by their respective speakers despite their languages being mutually unintelligible. However, languages that are classified within the Visayan language family but spoken natively in places outside of the Visayas do not use the self-reference "Bisaya" or "Binisaya". To speakers of Masbateño, Romblomanon, Surigaonon and Butuanon, the term "Visaya" usually refers to either Cebuano or Hiligaynon. Since Tausugs are mostly Muslims, they view the term "Bisaya" as a religious term referring to Christian Filipinos (mostly referring to either Cebuano and/or Hiligaynon as they are the neighboring languages).