Proto-Eskaleut, Proto-Eskimo–Aleut or Proto-Inuit-Yupik-Unangan is the reconstructed common ancestor of the Eskaleut languages, family containing Eskimo and Aleut. Its existence is known through similarities in Eskimo and Aleut. The existence of Proto-Eskaleut is generally accepted among linguists. It was for a long time true that no linguistic reconstruction of Proto-Eskaleut had yet been produced, as stated by Bomhard. Such a reconstruction was offered by Knut Bergsland in 1986. Michael Fortescue offered another version of Proto-Eskaleut, largely based on the reconstruction of Proto-Eskimo in the Comparative Eskimo Dictionary he co-authored with Steven Jacobson and Lawrence Kaplan .