Language exists in several channels in the brain: The Auditory, Visual and Haptic Modalities
Helen Keller, of course, who was not only deaf, but blind shattered that notion by acquiring not only language, but also speech!
In addition to analyzing language in terms of receptive, inner and expressive skills, we must remember that language can exist in more than one neurological channel (modality) within the brain.
Ignoring for the moment the olfactory (smell) and gustatory (taste) modalities, which are used by children to explore their environment, the channels we typically test, when analyzing language, are the Auditory, Visual and Haptic modalities.
The Auditory Modality consists of those neural networks that extend between the receptive (ear) and expressive transducers: the mechanisms for speech, Sign Language or pantomime.
NOTES: See the life and some thoughts of Hellen Keller.