Final answer:
Mrs. Pearce speaks the line to Professor Henry Higgins, cautioning him about his disregard for Eliza Doolittle's future while pursuing his phonetic experiment.
Step-by-step explanation:
The quote "Of course I know you don't mean her any harm; but when you get what you call interested in people's accents, you never think or care what may happen to them or you." is spoken by Mrs. Pearce in the play 'Pygmalion' by George Bernard Shaw. Mrs. Pearce is addressing Professor Henry Higgins and warning him about the potential consequences of his experiment with Eliza Doolittle's accent and manners. She expresses concern over Higgins's lack of consideration for Eliza's well-being beyond his academic interest.