Actually I believe only parts of Daniel, Ezra, and Jeremiah have Aramaic. You may be thinking of the Targum which are Aramaic translations of the Hebrew.
I'm certainly no bible scholar but I thought the Book of Daniel and the Book of Ezra were books in the Old Testament and were written, at least in part, in Aramaic.
Are you implying the gospels were originally written in Hebrew?......
No, not at all. There are many, however, who believe that the gospels are eye witness accounts written by the actual apostles. As these texts were originally written in Koine Greek these eye witnesses must have been fluent in that language.
With respect, I don't want to get into an argument over religion and this is drifiting off topic.