Henry Higgins, portrayed by Rex Harrison, is a conceited and irritable phonetics professor who boasts to Colonel Pickering, played by Wilfrid Hyde-White, about his ability to transform any woman into a refined speaker, capable of passing herself off as a duchess. His challenge comes to life with the arrival of Eliza Doolittle, a flower girl with a heavy Cockney accent, brought to life by the enchanting Audrey Hepburn. Determined to rise above her station, Eliza visits Higgins' residence, offering to pay for speech lessons in order to secure work at a flower shop. Intrigued, Pickering wagers that Higgins will fail, prompting him to undertake the challenge without charge.
Eliza's father, Alfred P. Doolittle, played by Stanley Holloway, appears three days later, claiming to be concerned for his daughter's virtue but actually seeking monetary gain from Higgins. Doolittle’s raw honesty, entertaining language, and unapologetic morality fascinate Higgins, especially when he quips, "Can't afford 'em!"
Eliza embarks on a rigorous training regimen, which includes quirky exercises such as speaking with marbles in her mouth and reciting the tongue-twisting phrase "In Hertford, Hereford, Hampshire, hurricanes hardly ever happen" without faltering on her 'h's. Initially, she struggles to make any progress due to Higgins' stern teaching methods. However, just as despair looms, Higgins delivers a passionate discourse on the profound beauty and history of the English language, igniting Eliza's determination to succeed. She finally masters the upper-class accent, showcasing her progress with remarkable elegance.
Higgins takes Eliza to her first public appearance at the Ascot Racecourse, where she manages to impress with her genteel manners—until a sudden slip into her Cockney roots shocks the crowd with the words, "C'mon Dover, move your bloomin' arse!" Higgins, who secretly disdains elitism, can’t help but smirk at her audacity.
The acknowledgment of Higgins' triumph comes during a ball at the embassy, where Eliza successfully passes herself off as a woman of noble lineage, even in the face of unexpected scrutiny from a Hungarian phonetics expert trained by Higgins himself. However, the story takes a poignant turn as Higgins exhibits callousness towards Eliza after the successful test, displaying a shocking disregard for her future. Feeling unappreciated and hurt, Eliza decides to leave, which leaves Higgins bewildered by her perceived ingratitude. In an unexpected moment of reflection, he realizes he has "grown accustomed to her face."
With his pride bruised yet determined, Higgins embarks on a quest to win Eliza back the following day, engaging in a strained conversation that only leads to further rejection from his former pupil. Predicting her downfall without him, he stubbornly indulges in playing old recordings of her lessons, until unexpectedly, Eliza reappears, bringing a wave of exhilaration to Higgins that starkly contrasts with his previous arrogance.
