how did Helen learn to read french?

From the text:

I found French much more difficult. I studied it with Madame Olivier, a French lady who did not know the manual alphabet, and who was obliged to give her instruction orally. I could not read her lips easily; so my progress was much slower than in German. I managed, however, to read "Le Médecin Malgré Lui" again. It was very amusing but I did not like it nearly so well as "Wilhelm Tell." ch 17