Jesus was quoting Aramaic. Not Septuagint. Aramaic was the spoken language of first century Israel.
According to first century Jewish historian, Josephus, Jews didn't speak Greek in first century Israel. He wrote:
"I have also taken a great deal of pains to obtain the learning of the Greeks, and understand the elements of the Greek language, although I have so long accustomed myself to speak our own tongue, that I cannot pronounce Greek with sufficient exactness; for our nation does not encourage those that learn the languages of many nations, and so adorn their discourses with the smoothness of their periods; because they look upon this sort of accomplishment as common, not only to all sorts of free-men, but to as many of the servants as please to learn them. But they give him the testimony of being a wise man who is fully acquainted with our laws, and is able to interpret their meaning; on which account, as there have been many who have done their endeavors with great patience to obtain this learning, there have yet hardly been so many as two or three that have succeeded therein, who were immediately well rewarded for their pains. – Antiquities of Jews XX, XI
Jewish Wars (Book 1, Preface, Paragraph 1):
I have proposed to myself, for the sake of such as live under the government of the Romans, to translate those books into the Greek tongue, which I formerly composed in the language of our country, and sent to the Upper Barbarians. Joseph, the son of Matthias, by birth a Hebrew, a priest also, and one who at first fought against the Romans myself, and was forced to be present at what was done afterwards, [am the author of this work]."
Aramaic Peshitta Tanakh is Aramaic Old Testament used among Jews in first century AD (source -http://www.pshitta.org/english/intro.php).
Josephus calls Aramaic as "our tongue" or "our language" or "the language of our country."
Jewish Wars Book 5, Chapter 4, Paragraph 2 – This new-built part of the city was called "Bezetha," in our language, which, if interpreted in the Grecian language, may be called "the New City."
"tha" at the end of "Bezetha" is the Aramaic definite article on a feminine noun in an emphatic state (Source – Book "Introduction to Syriac" by Wheeler Thackston, Page 44).