Different printed versions of the play omit or add certain lines. The Project Gutenberg version published online, for instance, omits Higgins' famous declaration to Eliza, "Yes, you squashed cabbage-leaf, you disgrace to the noble architecture of these columns, you incarnate insult to the English language! I could pass you off as the Queen of Sheba!" – a line so famous that it is now retained in nearly all productions of the play, including the 1938 film version of Pygmalion as well as in the stage and film versions of My Fair Lady.
The co-director of the 1938 film, Anthony Asquith, had seen Mrs. Campbell in the 1920 revival of Pygmalion and noticed that she spoke the line, "It's my belief as how they done the old woman in." He knew "as how" was not in Shaw's text, but he felt it added color and rhythm to Eliza's speech, and liked to think that Mrs. Campbell had ad libbed it herself. Eighteen years later he added it to Wendy Hiller's line in the film.
In the original play Eliza's test is met at an ambassador's garden party, offstage. For the 1938 film Shaw and co-writers replaced that exposition with a scene at an embassy ball; Nepomuck, the blackmailing translator spoken about in the play, is finally seen, but his name is updated to Aristid Karpathy – named so by Gabriel Pascal, the film's Hungarian producer, who also made sure that Karpathy mistakes Eliza for a Hungarian princess. In My Fair Lady he became Zoltan Karpathy. (The change of name was likely to avoid offending the sensibilities of Roman Catholics, as St. John Nepomuk was, ironically, a Catholic martyr who refused to divulge the secrets of the confessional.)
The 1938 film also introduced the famous pronunciation exercises "the rain in Spain stays mainly in the plain" and "In Hertford, Hereford, and Hampshire, hurricanes hardly ever happen". Neither of these appears in the original play. Shaw's screen version of the play as well as a new print version incorporating the new sequences he had added for the film script were published in 1941. The scenes he had noted in "Note for Technicians" are added.