From Muppet Wiki

Linda is a librarian who appeared on Sesame Street from 1972 to 2003. Linda was introduced on the show in Episode 0326, which aired in January 1972.

Linda is deaf, as is her performer. As a deaf character, Linda allowed the producers of Sesame Street to teach viewers about sign language and address issues faced by deaf people.

Linda and Bob were very close, and a romantic relationship between the two was implied at various times. Linda was the original owner of Barkley the dog.

Linda no longer appears on the show, but she is still mentioned in Sesame Street Magazine.