Henry Higgins is a professor of phonetics who plays Pygmalion to Eliza Doolittle's Galatea. He is the author of Higgins' Universal Alphabet, believes in concepts like visible speech, and uses all manner of recording and photographic material to document his phonetic subjects, reducing people and their dialects into what he sees as readily understandable units. He is an unconventional man, who goes in the opposite direction from the rest of society in most matters. Indeed, he is impatient with high society, forgetful in his public graces, and poorly considerate of normal social niceties--the only reason the world has not turned against him is because he is at heart a good and harmless man. His biggest fault is that he can be a bully.
"She is not at all a romantic figure." So is she introduced in Act I. Everything about Eliza Doolittle seems to defy any conventional notions we might have about the romantic heroine. When she is transformed from a sassy, smart-mouthed kerbstone flower girl with deplorable English, to a (still sassy) regal figure fit to consort with nobility, it has less to do with her innate qualities as a heroine than with the fairy-tale aspect of the transformation myth itself. In other words, the character of Eliza Doolittle comes across as being much more instrumental than fundamental. The real (re-)making of Eliza Doolittle happens after the ambassador's party, when she decides to make a statement for her own dignity against Higgins' insensitive treatment. This is when she becomes, not a duchess, but an independent woman; and this explains why Higgins begins to see Eliza not as a mill around his neck but as a creature worthy of his admiration.
Colonel Pickering, the author of Spoken Sanskrit, is a match for Higgins (although somewhat less obsessive) in his passion for phonetics. But where Higgins is a boorish, careless bully, Pickering is always considerate and a genuinely gentleman. He says little of note in the play, and appears most of all to be a civilized foil to Higgins' barefoot, absentminded crazy professor. He helps in the Eliza Doolittle experiment by making a wager of it, saying he will cover the costs of the experiment if Higgins does indeed make a convincing duchess of her. However, while Higgins only manages to teach Eliza pronunciations, it is Pickering's thoughtful treatment towards Eliza that teaches her to respect herself.
Alfred Doolittle is Eliza's father, an elderly but vigorous dustman who has had at least six wives and who "seems equally free from fear and conscience." When he learns that his daughter has entered the home of Henry Higgins, he immediately pursues to see if he can get some money out of the circumstance. His unique brand of rhetoric, an unembarrassed, unhypocritical advocation of drink and pleasure (at other people's expense), is amusing to Higgins. Through Higgins' joking recommendation, Doolittle becomes a richly endowed lecturer to a moral reform society, transforming him from lowly dustman to a picture of middle class morality--he becomes miserable. Throughout, Alfred is a scoundrel who is willing to sell his daughter to make a few pounds, but he is one of the few unaffected characters in the play, unmasked by appearance or language. Though scandalous, his speeches are honest. At points, it even seems that he might be Shaw's voice piece of social criticism (Alfred's proletariat status, given Shaw's socialist leanings, makes the prospect all the more likely).
Professor Higgins' mother, Mrs. Higgins is a stately lady in her sixties who sees the Eliza Doolittle experiment as idiocy, and Higgins and Pickering as senseless children. She is the first and only character to have any qualms about the whole affair. When her worries prove true, it is to her that all the characters turn. Because no woman can match up to his mother, Higgins claims, he has no interest in dallying with them. To observe the mother of Pygmalion (Higgins), who completely understands all of his failings and inadequacies, is a good contrast to the mythic proportions to which Higgins builds himself in his self-estimations as a scientist of phonetics and a creator of duchesses.
Higgins' surmise that Freddy is a fool is probably accurate. In the opening scene he is a spineless and resourceless lackey to his mother and sister. Later, he is comically bowled over by Eliza, the half-baked duchess who still speaks cockney. He becomes lovesick for Eliza, and courts her with letters. At the play's close, Freddy serves as a young, viable marriage option for Eliza, making the possible path she will follow unclear to the reader.