Prefatory context
Shaw opens with a programmatic preface: Pygmalion is born of his conviction that English orthography and accent perpetuate social injustice, and of his admiration for phonetics as a science and practical instrument of social mobility. He credits pioneers (Melville Bell, Alexander J. Ellis) and pays particular attention to Henry Sweet, whose personality and methods informed aspects of Professor Higgins though Shaw insists Higgins is not a portrait. The preface frames the play as intentionally didactic: an argument that language determines social reception and that scientific instruction can transform social identity.

Dramatic précis and principal characters
The play's central figures are Henry Higgins, an authoritative, philologically obsessed linguist; Colonel Pickering, his courteous fellow phonetician and patron; Eliza (Liza) Doolittle, a Cockney flower‑seller with quick apprehension and social aspiration; Mrs. Higgins, the cultured mother who supplies moral counterpoint; Alfred Doolittle, Eliza’s earthy, opportunistic father; and the Eynsford Hills (Freddy and his mother), representatives of genteel impecuniosity.

Act I — inciting incident
A storm in Covent Garden brings together Higgins, Pickering and Eliza. Higgins demonstrates his professional facility for regional identification and boasts that he could, within months, pass a Cockney as a duchess. Eliza, affronted by class prejudice, declares she wants to speak “more genteel” to obtain a shop job; Higgins, intrigued, proposes to teach her.

Act II — agreement and domestic arrangements
In Higgins’s laboratory Eliza offers to pay for lessons; Pickering wagers to fund an experiment: within six months she shall pass as a lady at an ambassador’s garden party. Practical tensions arise (cleanliness, manners, housekeeping). Doolittle appears demanding recompense; Higgins pays him off. Eliza undergoes cleansing and receives new clothing; the pedagogic project begins.

Act III — public trial
At Mrs. Higgins’s at‑home Eliza is exhibited and, by deliberate control of pronunciation and deportment, impresses society. Her linguistic success provokes both admiration and uneasy exposure of the limits of social assimilation: she can mimic high style, but her subject matter and origins remain awkwardly evident.

Act IV — psychological rupture
After triumph at a garden party, Eliza perceives that Higgins and Pickering treat the accomplishment as an intellectual game rather than an act that reorganizes her life. Feeling used and abandoned, she confronts Higgins; the quarrel exposes moral neglect—Higgins’s scientific triumph leaves Eliza socially dislocated.

Act V and postscript — resolution and exposition
Eliza briefly departs; Doolittle reappears, unexpectedly elevated by an American bequest, complicating financial claims. Mrs. Higgins mediates a reconciliation: Eliza refuses marriage to Higgins, insisting on self‑respect; Shaw’s supplied sequel (in narrative epilogue) explains that she ultimately marries Freddy, runs a modest flower/greengrocery enterprise, and maintains an ambivalent, combative friendship with Higgins.

Themes and critical note
Shaw explores language as social technology, the ethics of reform, class mobility, and gendered power. The play dramatizes the paradox of technical mastery without ethical responsibility: the scientist transforms a person’s speech but initially disregards the transformed person’s social and psychological needs. Shaw’s blend of satire, social critique and didactic intent is explicit: he defends didactic art and proposes phonetics as a lever of social justice.