addressing PR comments

Author: gregsdennis

proposals/vocabularies-adr.md

@@ -27,19 +27,23 @@ and a new Core keyword, `$vocabulary` to support it.
 
 ### Current design as included in 2019-09 and 2020-12.
 
-Vocabularies are external documents that describe how new keywords function.
-They can be in a specification style, or a blog post, or some other format.
+Vocabularies are collections of keywords and are defined by vocabulary document.
+For the 2019-09 and 2020-12 vocabularies, the documents are integrated into the
+specifications themselves.
 
-An implementation declares support for a particular vocabulary via
-implementation of its keywords and documentation.
+With vocabularies as the primary method for defining individual keywords,
+dialects can be created by combining different vocabularies.
+
+Users must confirm with an implementation's documentation whether a given
+vocabulary is supported.
 
 `$vocabulary` keyword is an object with URI keys and boolean values. The URIs
 identify each vocab, and the values indicate whether the implementation must
 "understand" that vocab in order to process the schema. This keyword is only
 processed when it is found as part of a meta-schema.
 
-* Good because it provides a language-agnostic mechanism that's built into JSON
-  Schema itself
+* Good because it provides a language-agnostic method of defining extension
+  keywords that's built into JSON Schema itself
 * Bad because unknown keywords are now unsupported, which implies that
   [unknown vocabularies are implicitly unsupported](https://github.com/orgs/json-schema-org/discussions/342)
 

proposals/vocabularies.md

@@ -67,7 +67,7 @@ support for them.
 
 ### Solution
 
-Two new concepts, vocabularies and dialects, will be introduced into the Core
+This proposal introduces vocabularies as a new concept to be added to the Core
 specification.
 
 A vocabulary is identified by an absolute URI and is used to define a set of
@@ -95,8 +95,9 @@ said to "include" that vocabulary.
 }
 ```
 
-A dialect is the set of vocabularies listed by a meta-schema. It is ephemeral
-and carries no identifier.
+Whereas in the current specification, a dialect is merely the set of keywords
+used by a schema, with this proposal a dialect is defined by the set of
+vocabularies listed by a meta-schema. It is ephemeral and carries no identifier.
 
 _**NOTE** It is possible for two meta-schemas, which would have different `$id`
 values, to share a common dialect if they both declare the same set of
@@ -195,13 +196,6 @@ unknown keywords presents a problem for schemas that use keywords from optional
 vocabularies. (This is the topic of the discussion at
 https://github.com/orgs/json-schema-org/discussions/342.)
 
-In short, if a schema uses a keyword from an unknown _optional_ vocabulary, the
-implementation cannot proceed because unknown keywords are explicitly
-disallowed. However, not being able to proceed with evaluation is the behavior
-prescribed for _required_ vocabularies. Thus, if the behaviors for required and
-optional vocabularies is the same, then the boolean value is moot, which
-highlights that the structure of `$vocabulary` needs to be reconsidered.
-
 #### Machine Readability
 
 The vocabulary URI is an opaque value. There is no data that an implementation