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1.
Languages of North Atlantic islands
Greenlandic is an Eskimo–Aleut language (of the Inuit branch). The others are Indo-European (of the North Germanic branch).
2.
Languages of the Balkans
All are Indo-European languages. Albanian is its own branch. The others are of the South Slavic branch.
3.
Languages of the former Yugoslavia
All are Indo-European languages of the South Slavic branch (which is the meaning of the word Yugoslav). Bosnian, Croatian, and Serbian (and also Montenegrin) are different standardized dialects of the Serbo-Croatian language. Slovenian is a separate language.
4.
Languages of Italy
All are Romance langauges. Sardinian is of the Southern Romance branch. The others are of the Italo-Western Romance branch.
5.
Languages of Mediterranean islands
Maltese is an Afro-Asiatic language (of the Semitic branch). The others are Indo-European.
6.
Languages of the ancient Near East
Sumerian is an isolate. The others are Afro-Asiatic.
7.
Turkic languages
All are Turkic languages of the Common Turkic branch. Kazakh is of the Kipchak branch. The others are of the Oghuz branch.
8.
Languages of Pakistan
All are Indo-European languages of the Indo-Iranian branch. Pashto is of the Iranian branch. The others are of the Indo-Aryan branch.
9.
Languages of the Horn of Africa
All are Afro-Asiatic languages. Amharic is of the Semitic branch. The others are of the Cushitic branch.
10.
Languages of Kenya
Luo is a Nilotic language. The others are Atlantic–Congo languages (of the Bantu branch).
11.
Languages of the Mozambique Channel region
Malagasy is an Austronesian language, brought to Madagascar by people from the Malay Archipelago. The others are Atlantic–Congo languages (of the Bantu branch).
12.
Languages of Namibia
Khoekhoe is a Khoe–Kwadi language. The others are Atlantic–Congo languages (of the Bantu branch).
13.
Languages of Indonesia
All are Austronesian languages, of the Malayo-Polynesian branch. Javanese is of the Javanesic branch. The others are of the Malayo-Sumbawan branch.
14.
Indigenous languages of Australia
Tiwi is an isolate. The others are Pama-Nyungan languages.
15.
Oceanic languages
All are Austronesian languages of the Oceanic branch. Fijian is its own branch within the Oceanic branch. The others are of the Polynesian branch.
16.
Indigenous languages of Alaska
Tlingit is a Athabaskan–Eyak–Tlingit (Na-Dene) language. The others are Eskimo–Aleut languages.
17.
Indigenous languages of Eastern Canada
Mohawk is an Iroquoian language. The others are Algic languages (of the Algonquian branch).
18.
Languages that share names with US states (more or less)
Miami-Illinois is an Algic language (of the Algonquian branch). The others are Siouan languages.
19.
Indigenous languages of the southeastern United States
Cherokee is an Iroquoian language. The others are Muskogean languages.
20.
Indigenous languages of the southwestern United States
Navajo is a Athabaskan–Eyak–Tlingit (Na-Dene) language (of the Athabaskan branch). The others are Uto-Aztecan languages (of the Numic branch).
21.
Indigenous languages of Mexico and Guatemala
Nahuatl is a Uto-Aztecan language (of the Aztec branch). The others are Mayan languages.
22.
Indigenous languages of Brazil
Kaingang is a Macro-Jê language (of the Jê branch). The others are Tupian languages (of the Tupi–Guarani branch)
23.
Languages that use the Geʽez (Ethiopic) script
All are Afro-Asiatic languages. Hadiyya is of the Cushitic branch. The others are of the Semitic branch.