MSCXXXX: Standardize the spec on US English

Signed-off-by: Johannes Marbach <n0-0ne+github@mailbox.org>

Author: Johennes

proposals/XXXX-en-us.md

@@ -0,0 +1,93 @@
+# MSCXXXX: Standardize the spec on US English 🇺🇸
+
+The spec's house style currently recommends British over American English[^1]. This has historically
+not been strongly enforced, however. For instance, there are multiple instances of both "authorize"
+(🇺🇸) and "authorise" (🇬🇧) in the spec text as well as in identifiers such as `M_UNAUTHORIZED` and
+`m.unauthorised`. While this inconsistency usually doesn't hinder readability, it negatively impacts
+searchability and general consistency of the spec.
+
+Standardizing on British English is difficult though because many other technical standards use the
+American spelling. For instance, RFC6749 defines the term "authorization server"[^2] as well as the
+`authorization_code` grant type[^3] as an identifier. Using the British spelling when covering these
+in the Matrix spec would be confusing for terms and impossible for identifiers.
+
+For comparison, the following noteworthy standards use American English:
+
+- W3C[^4]
+- IEEE[^5]
+- ANSI[^6]
+
+In contrast, the following standards enforce British English:
+
+- ISO[^7]
+
+Lastly, these standards allow either of the two as long as they are used consistently within a
+document:
+
+- RFCs[^8]
+
+Given the dominant use of US English in other standards and the unsolvable problem of localizing
+identifiers, this proposal seeks to standardize Matrix on US English.
+
+## Proposal
+
+The spec's house rules are updated to RECOMMEND the American over the British spelling. Existing
+spec text and identifiers are not updated but MAY be migrated in future. Any new spec text or
+identifiers SHOULD use the American spelling.
+
+## Potential issues
+
+This proposal doesn't directly resolve the current inconsistency of both spellings being used in the
+spec simultaneously. It paves the way for an eventually consistent spelling without the need for
+busywork, however.
+
+Many of the spec contributors and especially members of the core team have a British background.
+Departing from their native spelling might feel odd for some.
+
+Matrix has a huge center of mass in Europe. In a time of transatlantic tension, committing to the
+American spelling might feel uncomfortable to some. Language and politics should not be conflated,
+however.
+
+## Alternatives
+
+We could enforce the British spelling in spec text and identifiers that are not inherited from other
+standards. To aid searchability, a legend of common words that differ in spelling could be included
+at the bottom of each page.
+
+    authorise -> authorize
+    authorisation -> authorization
+    ...
+
+A reader searching for "authorization" would at least land on the legend and receive a cue to search
+for "authorisation" instead. This feels more complicated and less practical than standardizing on US
+English, however.
+
+## Security considerations
+
+None.
+
+## Unstable prefix
+
+None.
+
+## Dependencies
+
+None.
+
+[^1]: <https://github.com/matrix-org/matrix-spec/blob/bb3daafe96cce7ec7e139223429d2ea93e087c08/meta/documentation_style.rst?plain=1#L50>
+
+[^2]: <https://datatracker.ietf.org/doc/html/rfc6749#section-1.1>
+
+[^3]: <https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.3>
+
+[^4]: <https://www.w3.org/guide/manual-of-style/#Spelling>
+
+[^5]: <https://sagroups.ieee.org/1588/wp-content/uploads/sites/144/2020/05/2014-ieee-sa-standards-style-manual.pdf>
+    "under 19.2 c"
+
+[^6]: <https://www.ansi.org/american-national-standards/ans-introduction/essential-requirements>
+    "4.0 only mentions "English" but it is the **American** National Standards Institute"
+
+[^7]: <https://www.iso.org/ISO-house-style.html#spelling>
+
+[^8]: <https://www.rfc-editor.org/rfc/rfc7322.html#section-3.1>