A Shavian play (i.e. a play by GB Shaw or with the characteristics of writing of GB Shaw) reunites many elements which make them unique: The dialogue is smart, quick, witty, funny, and sharp. The characters are laughable, provincial, bucolic, ridiculous, and do not behave with politeness nor mannerisms expected of the fashionable society. The situation of the story is accentuated by references to the classics, (like Ovid's Metamorphoses as the central plot to the story related in a Shavian way), and using literary techniques that include irony, sarcasm, and puns.
In the main characters, as well as in he character of the phonetic professors, we see all this taking place:
A provincial girl who is paying for lessons to get rid of her cockney accent so that she can sound elegant.
The need to transform her to pretend to be a duchess.
The implication that society would accept anyone who just appears to be rich (ignorant society).
The exaggerated language and the fights between the characters.
All these are the main Shavian characteristics of Pygmalion.