Suddenly she stopped short, and disengaged herself from her companion. 'Oh, I sy,' she said, 'this is too bloomin' slow; it gives me the sick.' That is not precisely what she said, but it is impossible always to give the exact unexpurgated words of Liza and the other personages of the story, the reader is therefore entreated with his thoughts to piece out the necessary imperfections of the dialogue.
Source: wiktionary