Consistency.SpellingDialect

Tallies British against American spellings across the project, then flags the minority. A codebase that writes "behaviour" in 40 places and "behavior" in three does not have two conventions; it has one convention and three outliers.

What it reads

In TypeScript: comments, doc comments and prose-shaped string literals. Nothing else.

Identifiers are never scanned, and that is the load-bearing constraint rather than an oversight. normalize, serialize, initialize and CSS color are API surface: renaming a function to satisfy a prose convention would break callers to fix nothing. A string literal counts as prose only if it contains a space, which keeps import specifiers, object keys and check ids out of the tally for the same reason.

In Markdown: the document body. The whole file is prose, so the TypeScript rule has no analogue; what is excluded instead is the code a page quotes — fenced blocks, inline code spans, link destinations and YAML frontmatter. A page documenting a normalize option or linking to color-scheme.md is reporting an American spelling, not writing one. Indented code blocks are not excluded, because four spaces is also how a nested list continuation is written and silencing every one of those would cost more prose than the rule buys.

Markdown files are discovered only when a project opts in with [engine] extra_extensions = ["md"]. Without it the corpus is the code half alone, and a project whose documentation and code disagree sees one side of the disagreement.

Which dialect

By default, whichever the project already uses. The check ships no opinion — deciding which dialect a team should write is a different and much harder question than noticing the team has not decided, and only the second is something a static analyser can answer.

Three things follow from that. The check says nothing until the project has at least eight dialect-carrying words, below which a majority is a coincidence. It says nothing on a close split or a tie, because a project that has not chosen is not a project in violation. And when it does fire, the message names the majority spelling rather than a house style.

A team that has chosen can say so:

[checks."Consistency.SpellingDialect"]
dialect = "british"   # or "american"

With a dialect pinned the minimum-occurrence floor and the majority rule both fall away: every deviation is reported, however few.

Word list

Deliberately short. The -ise/-ize family plus the high-frequency pairs that turn up in software prose — behaviour, colour, catalogue, centre, defence, artefact and their inflections. It is a list, not a dictionary, and it is meant to stay that way: a rule that fires on a word nobody meant to standardise is worse than one that misses a few.

Two pairs are left out on purpose. licence/license splits by part of speech in British English, so both spellings are correct in the same document. programme/program is not a dialect pair at all where software is concerned — "program" is the British spelling too.

Suppression

The usual // cofferdam-disable-next-line Consistency.SpellingDialect, or a severity override for a directory that quotes external prose verbatim.