Helen Keller was deaf and blind. Apparently, she ;learnt sign language but she could not hear or see so how is that

Question: Helen Keller was deaf and blind. Apparently, she ;learnt sign language but she could not hear or see so how is that possible?
- Keywords:
  helen keller,
  language,
  sign
Asked by Rasheeda1124 to Andy, Diana, James, Mary Jane, Wil on 14 Mar 2017.
- Wilhelmiina Toivo answered on 14 Mar 2017:
  
  I actually hadn’t heard of her before so I had to look it up online. Looks like she was a very determined person, I’m really impressed with her story! I think she learnt language through touch of her teacher and this is how she managed – sign language is based on hand motions so feeling them would also work.
- Diana Kornbrot answered on 14 Mar 2017:
  
  Yes. she definitely communicated by touch. touch languages sich as Britisg Sign Language [BSL} are as rich as spken languages
  Shew was also able to learn about the world by touch, recognizing objects and her location in space

Question: Helen Keller was deaf and blind. Apparently, she ;learnt sign language but she could not hear or see so how is that possible?