Final answer:
Higgins' ironic concern for Liza's manners in Shaw's 'Pygmalion' highlights his own lack of manners, creating a classic example of dramatic irony and character inconsistency.
Step-by-step explanation:
The irony in the exchange between Mrs. Pearce and Higgins in Shaw's Pygmalion is that Higgins is concerned about Liza's manners when he does not have any himself. This example of dramatic irony underscores the inconsistency in Higgins' character as a professor of phonetics who fails to recognize his own shortcomings while expecting high standards from others.
The audience is aware of Higgins' crude behavior at times, which contrasts with his concern for propriety regarding Liza, adding humor and depth to his character.