"Liza Doolittle." The cockney girl is not only dirty, in need of a dentist, unfashionable and common but also has a coarse, even painful, voice and badly pronounced language. Despite of Eliza's flaws we feel sorry for her and her likeability stands out. Eliza takes the initiative, after hearing Henry Higgins's boast, to change the way she is. "I want to be a lady in a flower shop stead of sellin' at the corner of Tottenham Court Road". Eliza goes to Higgins's lab in Wimpole Street.
Eliza tries to clean herself up by washing her hands and face and offers to pay Higgins for phonetics lessons all in the effort to make herself equal to those around her. "Did you tell them I come in a taxi?" Eliza knows that she'll have to act like a lady as well as talk like one but she must also look like a duchess. Mrs Pearce, the fiery housekeeper to Henry Higgins, will often speak her mind to Higgins especially on her thoughts of Eliza. Mrs Pearce makes Eliza look like a lady by bathing her and dressing her in the day's fashions. Doolittle, Eliza's father, stands out of Eliza's way when she is clean and nicely dressed. "Don't you recognize your own daughter?" This shows that asceticism is important in the distinction of the classes.
Professor Henry Higgins believes that phonetics will change Eliza into a duchess. Eliza learns to speak properly and she is accepted by the Eynsford-Hills when before, in Covent Garden, she was rejected by them. This means that phonetics also made Eliza into a duchess.
However, Eliza did not have social niceties and had to learn not only how to speak but what to speak about. "Of course she's not presentable, if you suppose for a moment that she doesn't give herself away in every sentence she utters you must be perfectly cracked about her." She obviously needs social ability to be more Lady like.
Colonel Pickering and Higgins are very different in the way that they treat Eliza. Pickering treats Eliza with respect and makes her confident and Higgins bullies her though I believe both make her into a duchess. Higgins' bullying and mean remarks make Eliza strong. "I'm not afraid of you, I can do without you." Pickering treated her as she ought to be treated, giving her the power, confidence and bravery to stand up to Higgins.
In conclusion, I believe that like many things, it was not one aspect that changed Eliza. She couldn't have become a 'duchess' without aesthetics, phonetics and social ability and a Lady wouldn't take Higgins' bullying. But, Higgins and Pickering did teach Eliza an unexpected lesson - it is not how you look or how you speak that matters, but the treatment you receive. For even if Higgins 'treats a duchess like a flower girl', Pickering will always 'treat a flower girl like a duchess'.