In fact, at the time of PYGMALION’s debut, the standard International Phonetic Alphabet had not yet been created (though I think they were working on it).
There was a marvelous production of My Fair Lady in Boston a few years ago (I subbed in as music director for a week of it), and the set design included panels that had International Phonetic Alphabet symbols all over them. (Never mind whether that was anachronistic or not, lol.) I remarked that in this production, you got your IPA during the show, instead of waiting to go out for one afterwards. :-)