One side of Glasgow (6)
I believe the answer is:
celtic
This clue might be a double definition.
'one side' is the first definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'glasgow' is the second definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for celtic that I've seen before include "This tiger is credited with Irish prosperity" , "Roy Keane's team on the fringe" , "The race of ancient Gaels" , "Like, eg, Welsh, Gaelic" , "Group of languages including Irish, Welsh, etc" .)