Of course he had betrayed his ignorance and rusticity in a hundred little ways.

Although he began to understand a little of what passed around him in the interlarded speech of the day, he could not frame his tongue to any adequate imitation of it yet.

He had learnt, alas, to swear in his old life; but there is a fashion even in oaths, and his were too rustic in form to pass muster here.
As the bully beaux got deeper in their cups, so did their baiting of young Tom increase in offensiveness and coarseness.

The hot flush of anger kept rising in the young man's face, and there were moments when a fight was imminent, which was perhaps what the aggressors desired.

Harry was still in the outer room, or he would have interposed, for it was not a nice thing to be the butt of a set of braggarts and bullies, and this fashion of drawing a young man into their clutches was by no means unusual.
Suddenly, as matters seemed to be getting ripe for some outbreak of fury on Tom's part, which might well lead to disastrous results, a sudden clear, resonant voice rose above the hubbub, and dominated all other tones by a peculiar property impossible to describe.
"Let that lad alone, you cowards!" spoke the voice, in tones of unmistakable authority.