Acts 22:1-3

When they heard him speaking to them in Hebrew. The Aramaic or Chaldee dialect of Hebrew was the standard language which every Jew could speak and understand. Even though their "native language" (see Acts 2:8 and note) might be different, all were taught Hebrew in the synagogue schools. I am a Jew. To disprove their charge that he prejudiced people against the Jews, he shows that he is himself a Jew, brought up in Jerusalem [but evidently not here during Christ's public ministry, crucifixion and resurrection], educated in the Law by Gamaliel (see Acts 5:34). And was just as dedicated to God. Note how he makes himself one of them! This is his first opportunity to explain to the Jewish leaders the reason why he had become a Christian.