Maliseet and Mi'kmaq are very closely related to each other. This means that they separated relatively recently, and therefore within the Maritime region. They were the only languages spoken in the present-day Maritime provinces when the first Europeans arrived.
Of course, the Indians of that time would have known the languages of the other peoples with whom they traded, in New England and around the Gulf of St. Lawrence - Iroquoian languages in the Gaspe and to the west, other Algonquian Languages to the north and south, Beothuk in Newfoundland, Montagnais in Quebec and Labrador.
Not all the Algonquian languages are equally close relatives. Just as there are sub-groups among the Indo-European languag es - such as Romance, Germanic, Slavic - so, too, there are sub-groups of the Algonquian languages.
One of these is Eastern Algonquian, which today includes, in addition to Maliseet and Mi'kmaq, Abenaki in Quebec and Passamaquoddy and Penobscot in Maine. Of these, only Maliseet, Passamaquoddy and Mi'kmaq are widely spoken. There are just a few people who speak Penobscot or Abenaki today.
Maliseet is often called Maliseet-Passamaquoddy because the two languages are really dialects of the same language, with only a few minor differences between them, much like British and Canadian English - a few vocabulary words, pronunciation and accent.
Passamaquoddy is spoken in the St. Croix River watershed, in Maine, and Maliseet along the St. John River in New Brunswick. There is a Maliseet band in Houlton, Maine, and other speakers live elsewhere in New Brunswick and New England.
Speakers of Mi'kmaq live in the Gaspe Peninsula, in northern and eastern New Brunswick, and in Nova Scotia and Prince Edward Island. There are also communities of Mi'kmaq in Conne River, Newfoundland; in Aroostook County, Maine; and in Boston, Massachusetts. Many speakers live in other communities in the Atlantic provinces and New England.
There are several dialects of Mi'kmaq. Mi'kmaq in Cape Breton do not speak exactly like Mi'kmaq in New Brunswick or Quebec. But all speakers of Mi'kmaq can understand one another easily.