Martin McNamara writes: “All of Josephus’ four extant works are important sources for Jewish history and tradition. The first to be composed was The Jewish War—an account of the war of the Jews against the Romans. Josephus himself tells us that he wrote two versions of this. ********The first one was in his own vernacular, i.e. Aramaic, and composed for ‘the up-country barbarians’, i.e. the Aramaic-speaking Jews of the Parthian kingdom, especially those of Babylon. This edition is lost.********** The extant Greek version is an adaptation by Josephus himself of the Aramaic work. It was published about A.D. 78, when Josephus was about 40 years old. The next work to be published was The Jewish Antiquities, about sixteen years later (A.D. 94 or so). It appears that soon before the publication of The Antiquities Justus of Tiberias had published his history of the Jewish War, with serious accusation of misconduct during the war in Galilee directed against Josephus. It is possible that Josephus’ third and autobiographical work, the Life, was published at the same time as the Antiquities and as a reply to Justus. Some scholars, however, maintain that the Life was published about A.D. 96, and may have appeared together with a second edition of the Antiquities that appeared between A.D. 93/94 and 100. Josephus’ final extant work to be published was Against Apion, or to give its original title, On the Antiquity of the Jews. In the first part of this work Josephus sets out to refute the detractions and contentions of anti-Semitic writings. In the course of doing so he excerpts from a large number of works no longer extant. In the second part Josephus gives his positive defence of the Jewish people, setting forth the inner value of Judaism and its superiority over Hellenism. In this we have a rather full presentation of Jewish halakah as known to Josephus.” (Intertestamental Literature, p. 239) http://www.earlyjewishwritings.com/josephus.html
And if you have $32!!!: http://www.jstor.org/discover/10.2307/4477386?uid=3739672&uid=2&uid=4&uid=3739256&sid=21102434339177
http://www.hebrew4christians.com/Articles/Jesus_Hebrew/jesus_hebrew.html
This webpage should help clear up some of your questions. You come closest to being right suggesting the possibility that Hebrew was primarily spoken in Jerusalem while a dialect of Aramaic was the language of Galilee. When Jesus spoke to his Galilean disciples it was most likely in Aramaic, but he was fluent in Hebrew and Greek. The Samaritans spoke Hebrew. When Jesus spoke to Paul on the road to Damascus it was in Hebrew. Paul was fluent in Hebrew, and he used it when addressing the people of Jerusalem.
I recently read an excellent paper on this subject, and I can’t find it, though it should have been stored on this computer. There is plenty of research that lays to rest the misconception that Aramaic was the only language, or even the primary language of most Jews during the time of Jesus. Hebrew was very much alive and well, and spoken as a common language, in addition to being the language of the Torah and the temple.