Heathcliff befriends Hindley's son, Hareton and teaches him to curse, act disrespectfully, call his father names, and to pretty much ignore anything his father tries to teach him.
He raised his missile to hurl it; I commenced a soothing speech, but could not stay his hand: the stone struck my bonnet; and then ensued, from the stammering lips of the little fellow, a string of curses, which, whether he comprehended them or not, were delivered with practised emphasis, and distorted his baby features into a shocking expression of malignity. You may be certain this grieved more than angered me. Fit to cry, I took an orange from my pocket, and offered it to propitiate him. He hesitated, and then snatched it from my hold; as if he fancied I only intended to tempt and disappoint him. I showed another, keeping it out of his reach.
'Who has taught you those fine words, my bairn?' I inquired. 'The curate?'
'Damn the curate, and thee! Gie me that,' he replied.
'Tell us where you got your lessons, and you shall have it,' said I. 'Who's your master?'
'Devil daddy,' was his answer.
'And what do you learn from daddy?' I continued.
He jumped at the fruit; I raised it higher. 'What does he teach you?' I asked.
'Naught,' said he, 'but to keep out of his gait. Daddy cannot bide me, because I swear at him.'
'Ah! and the devil teaches you to swear at daddy?' I observed.
'Ay - nay,' he drawled.