What Shahrur Says
The cited passage gives a direct definition of bayān: “Bayān: the capacity for expression and understanding; it is acquired through education, not merely the organ of speech.”
Atlas Explanation
The definition specifies the subject at hand: bayān is a capacity connected with expression and understanding, rather than merely the physical organ. Describing it as acquired through education shows that learning is part of this conception of bayān.
Limited Inference
This definition can be read as shifting bayān from the level of the organ alone to that of capacity. The broader implications of this, however, cannot be established from this passage alone.
Open Question and Limits of the Evidence
The passage does not explain how bayān is acquired through education, nor does it specify the extent of its relation to freedom or responsibility. Its available location is also limited to a reference to the first section of the book.