There are 8 indigenous languages spoken in Minahasa Raya: Tonsea, Tondano, Tombulu, Tontemboan and Tonsawang, Bantik, Ratahan and Ponosakan. The first five languages form a genetic group called proto-Minahasan. They are more closely related to each other and cover the greater part of Minahasa Raya. It is therefore reasonable to assume that they all derive from a common parent language which was itself spoken in Minahasa. J. N. Sneddon made the following classification:

The other three languages have their closest links with languages spoken outside Minahasa Raya. Ponosakan is closely related to Mangondow (B), spoken in Bolaang Mangondow District to the south of Minahasa District.    Ratahan, also referred as Bentenan, and Bantik have their closest links with Sangir, spoken on the islands of Sangir Archipelago to the north of Minahasa District. The use of these languages, however, is decreasing as many people especially the younger generation are under pressure to switch to Manadonese, also known among the local people as Malayu Pasar or Manado Malay.

Besides these languages, there many people who speak Sangir (S), especially in Bitung, the northen coasts of Minahasa and the small islands. SIL International projects the languages distribution in the following map (modified):

BANTIK (1) is spoken by about 6,000-11,000 (1991) people in about ten villages surrounding Manado, the provincial capital of North Sulawesi and several transmigration villages in southern Minahasa. The language is most closely related to Sangir.
 

MALAY, MANADONESE (2) (MANADO MALAY, MANADONESE MALAY,MENADO MALAY, MINAHASAN MALAY) Most people in Minahasa Raya speak this language or at least understand it. As the name suggests, this language is a variant of Malay which in various degrees is modified by replacing lexical items.

PONOSAKAN (3) (PONOSAKAN) is spoken by 2,000 people (survey done in 1991) in three villages in the district of Ponosakan in the south-eastern part of Minahasa and is most closely related to Mongondow.

RATAHAN (4) (BENTENAN, PASAN) is spoken by 30,000 people (1989) in the north-eastern section of the northern peninsula of Sulawesi, around Ratahan and to the southeast coast of the northern peninsula.
 

TOMBULU (5) (TOMBULU', TOMBULA, TOUMBULU, TOMBALU, MINAHASA, MINHASA) is spoken by 60,000 people (1981) in the center of Minahasa to the west coast, around Tanawangko and Tomohon. Dialects: TARATARA, TOMOHON. Closest to Tondano and Tonsea.

TONDANO (6) (TONDANOU, TOLOU, TOLOUR, TOULOUR) is spoken by 92,000 people in Indonesia (1981); 20 to 25 in USA. Northeastern Sulawesi around Tondano and to the southeast coast of the northern peninsula. Dialects: TONDANO, KAKAS (KA'KAS), REMBOKEN. Closest to Tombulu and Tonsea.

TONSAWANG (7) (TOMBATU) is spoken by 20,000 people (1981). This language is spoken in about a dozen villages around Tombatu in the southern part of Minahasa Regency.

TONSEA (8) (TONSEA') is spoken by 90,000 people (1989). This language is spoken in the extreme north part of the Sulawesi peninsula and has the largest area of any Minahasan language. The dialects are insignificant. Dialects: MAUMBI, AIRMADIDI, LIKUPANG, KAUDITAN, KLABAT, BITUNG. 

TONTEMBOAN (9) (TOMPAKEWA, TOUNTEMBOAN, PAKEWA) is spoken by 150,000 (1990) in the northeastern coast of Minahasa Peninsula from Sonder to around Motoling and Tompasobaru. Dialects: LANGOAN, TOMPASO (MAKELAI, MAKELA'I-MAOTOW), SONDER (MATANAI, MATANA'I-MAORE'). 

Sources:
1). J. N. Sneddon: Proto-Minahasan: Phonology, Morphology and wordlist. Department of Linguistics Research,
       School of Pacific Studies, The Australian National University. 1978
2). SIL International