That he spake Hebrew. This is indeed an usual thing, that when men which speak diverse languages are together, we hear those more willingly who speak our own language; but the Jews were moved with another peculiar cause, because they imagined that Paul was offended [1] with his own kindred, so that he did even hate their tongue, or that he was some rogue which had not so much as learned the speech of that nation whereof he said he came. Now, so soon as they heard their own language, they began to have some better hope. Furthermore, it is uncertain whether Paul spake in the Hebrew or in the Syrian tongue; for we know that the speech of the Jews was corrupt and degenerate after their exile, forasmuch as they had much from the Chaldeans and Syrians. For mine own part, I think, that because he spake as well to the common sort as unto the elders, he used the common speech which was at that day usual.

Footnotes

1 - "Ex professo infensum," professedly hostile to.

The Hebrew tongue - See the notes on Acts 21:40.

When they heard that he spake in the Hebrew tongue - He had probably been traduced by the Jews of Asia as a mere Gentile, distinguished only by his virulence against the Jewish religion; which virulence proceeded from his malice and ignorance.

And when they heard that he spake in the Hebrew tongue to them,.... See Gill on Acts 21:40.
they kept the more silence; it being their mother tongue, and which they best understood; and which the captain and the Roman soldiers might not so well under stand; and chiefly because the Hellenistic language was not so agreeable to them, nor the Hellenistic Jews, who spoke the Greek language, and used the Greek version of the Bible; and such an one they took Paul to be, besides his being a Christian; wherefore when they heard him speak in the Hebrew tongue, it conciliated their minds more to him, at least engaged their attention the more to what he was about to say:
and he saith; the Syriac and Ethiopic versions add, "to them", as follows.

PAUL'S DEFENSE FROM THE STAIRS OF THE FORTRESS--THE RAGE OF THE AUDIENCE BURSTING FORTH, THE COMMANDANT HAS HIM BROUGHT INTO THE FORT TO BE EXAMINED BY SCOURGING, BUT LEARNING THAT HE IS A ROMAN, HE ORDERS HIS RELEASE AND COMMANDS THE SAMHEDRIM TO TRY HIM. (Acts 22:1-30)
when they heard . . . the Hebrew tongue--(See on Acts 21:40).
they kept the more silence--They could have understood him in Greek, and doubtless fully expected the renegade to address them in that language, but the sound of their holy mother tongue awed them into deeper silence.