Definition for accessibility requirement
Although EN 301 549 contains an extremely broad definition of the term "accessibility", there is no definition of the term "accessibility requirement" even though the term is used many times in important places, most notably in the Conformance clause (14). To avoid people interpreting "accessibility requirement" to mean any requirement related in any way to the broad concept of "accessibility", the term must be separately defined to have a clear meaning that aligns with widely accepted meanings of the term.
An initial proposal for the definition is the following:
requirements that specify that something is made available to a user with one or more disabilities in order for that user to use a product or service that would not be needed by users without disabilities to be able to use the product or service.
I am hesitant that the breadth of the term "something" may allow people to designate inappropriate requirements as accessibility requirements, but tightening that wording to narrow its scope can be controversial!
After the following comments, the current proposed definition becomes:
accessibility requirement: requirement that specifies a capability, which would not normally be needed by users without disabilities, which is made available to a user with one or more disabilities to allow that user to use the product or service.
EXAMPLE: The addition of RTT to voice calls enables deaf users, who are unable to participate in voice conversations, to engage in text conversations. The RTT capability will also allow users who normally speak to each other to move their conversation to RTT when trying to communicate in very noisy environments or where is not possible to use audio (e.g. silence areas, missing headphones, etc.).