As you can see from this map of the Atlantic (Native American) coastal languages, all the midcoast Maine languages are considered to be Algonquian.  Katahdin: Wigwam's tales of the Abnaki tribe by Molly Spotted Elk contains a dictionary for the Penobscot language.  J. Dyneley Prince and Frank Speck, have recently published Volume 9: A vocabulary of Mohegan-Pequot part of the American Language Reprint Series.  This series contains texts on many Native American languages.

ahwangan: Whenever Native American canoeists had to go from one watershed to another they had to unload each canoe and carry both the canoe and the wangan across the portage.  This is the origin of the word "ahwangan," the ancient Native American term designating the portage from one navigable stream to the next.  As with most Native American words, ahwangan is a metaphor for the laborious process of traveling from one watershed to the next, carrying both canoe and canoe cargo overland. (Mike Krepner, Native Trails)
Almouchiquois: Souriquois: they referred to this other tribe literally as 'dog people' (Bourque, Twelve Thousand Years)
Ma-voo-shan or Mo-a-aap: a country bounded east by Tarratines or Penobscots and south on the sea.  The chief was called Bashaba.  (Sewall, Mavooshen)
mecadacut  or megunticook: Penobscot: "/amehkáyihtekok/ 'at a stream below a height (or mountain)', which is better retained by the modern spelling found in the present Megunticook River.  Near-by is Mt. Megunticook which rises to a height of 1380 feet, and is the southern-most mountain or headland of the Appalachians to stand directly on the Atlantic coast." (Siebert, The identity of the Tarrentines, with an etymology)
Mo-a-shans: The people of Ma-voo-shan, those found at Pemaquid. (Sewall, Mavooshen)
muskingum: as elk's eyes or deer eyes (Boyd, Indian local names with their interpretation)
Nolumbeka: Abenaki: means either a stretch of quiet water between two rapids, or a succession of rapids interspersed by still waters. This exactly fits the Penobscot River above Bangor. Father Vetromile, a missionary to the Abnaki at Old Town, notes that Indians were still using that name for their region in 1866. (Morison, The European Discovery of America)
Oranbega: First appears on Girolamo da Verrazzano's map dated 1529 and appears to be the Penobscot River. (Morison, The European Discovery of America)
ornbega:  native word: This term identifies the lower portion of the Penobscot River, the only native name on Verrazzano's map (Snow, The Ethnohistoric Baseline of the Eastern Abenaki)
Sagadahoc: Abnaki: the outflowing of a swift stream as it meets the sea. (Huden, Indian Place Names of New England)
wangan: an old Indian word, refers to all the impedimenta associated with canoe travel. (Cook, Indian Canoe Routes of Maine, pg. xiv).