Adam Clarke on Acts 19:10

By the space of two years - The schoolhouse of Tyrannus was his regular chapel; and it is likely that in it he taught Christianity, as Tyrannus taught languages or sciences.

All they - in Asia heard the word - Meaning, probably, the Proconsular Asia, for the extent of which see the note on Act 16:6.

Jews and Greeks - For, although he ceased preaching in the synagogues of the Jews, yet they continued to hear him in the school of Tyrannus. But it is likely that Paul did not confine himself to this place, but went about through the different towns and villages; without which, how could all Asia have heard the word? By Greeks, we are to understand, not only the proselytes of the gate, but the heathens in general.