the high-pitched dominance of his nature

He was a civilized man, that was what he was, shoulder to shoulder, at dinner, with people he had read about in books. He was in the books himself, adventuring through the printed pages of bound volumes.
But while he belied Arthur's description, and appeared a gentle lamb rather than a wild man, he was racking his brains for a course of action. He was no gentle lamb, and the part of second fiddle would never do for the high-pitched dominance of his nature. He talked only when he had to, and then his speech was like his walk to the table, filled with jerks and halts as he groped in his polyglot vocabulary for words, debating over words he knew were fit but which he feared he could not pronounce, rejecting other words he knew would not be understood or would be raw and harsh. But all the time he was oppressed by the consciousness that this carefulness of diction was making a booby of him, preventing him from expressing what he had in him. Also, his love of freedom chafed against the restriction in much the same way his neck chafed against the starched fetter of a collar. Besides, he was confident that he could not keep it up. He was by nature powerful of thought and sensibility, and the creative spirit was restive and urgent. He was swiftly mastered by the concept or sensation in him that struggled in birth-throes to receive expression and form, and then he forgot himself and where he was, and the old words - the tools of speech he knew - slipped out.
Once, he declined something from the servant who interrupted and pestered at his shoulder, and he said, shortly and emphatically, "Pew!"
On the instant those at the table were keyed up and expectant, the servant was smugly pleased, and he was wallowing in mortification. But he recovered himself quickly. He paused, open-mouthed, on the verge of the pit of his own depravity and utter worthlessness to breathe the same air she did. And while Arthur took up the tale, for the twentieth time, of his adventure with the drunken hoodlums on the ferry-boat and of how Martin Eden had rushed in and rescued him, that individual, with frowning brows, meditated upon the fool he had made of himself, and wrestled more determinedly with the problem of how he should conduct himself toward these people. He certainly had not succeeded so far. He wasn't of their tribe, and he couldn't talk their lingo, was the way he put it to himself. He couldn't fake being their kind. The masquerade would fail, and besides, masquerade was foreign to his nature. There was no room in him for sham or artifice. Whatever happened, he must be real. He couldn't talk their talk just yet, though in time he would. Upon that he was resolved. But in the meantime, talk he must, and it must be his own talk, toned down, of course, so as to be comprehensible to them and so as not to shook them too much. And furthermore, he wouldn't claim, not even by tacit acceptance, to be familiar with anything that was unfamiliar. In pursuance of this decision, when the two brothers.