Like Bell and most educators at the time, Edward Gallaudet, founder and President of the National College for Deaf-Mutes (now Gallaudet University) worried that reliance on “gesture language” would hinder a child’s ability to understand and think in English. At a conference in Indiana in the 1880s, Gallaudet said that reliance on what he called “gesture language” could be a “great danger.” 
A few years later, Gallaudet was quoted by one of his professors as saying, “If we want the children of our institutions for the deaf and dumb to master the English language, what have we to do with the sign-language? I answer, as little as possible.”
Eventually, Gallaudet became more supportive of the rudimentary sign language that his father Thomas had begun to develop. But it was a far cry from today’s sophisticated ASL
4. Quoted by Bell in his testimony in the National Education Association conference, Proceedings of meeting held in the Senate chamber, Madison, Wis., Wednesday, July 16th, 1884.
5. Quoted by Prof. Gordon of Gallaudet University.