Heading capitalization rules must be consistent

What it is

Locale-scoped capitalization style defines casing for headings, buttons, menus, notifications, and other component roles within each language and script, then keeps that decision consistent inside its scope. English may use sentence case, title case, or a platform convention, but English title case is neither a rule for every Latin-script language nor a global template for scripts without letter case. What stays consistent is an explainable style decision, not one surface transformation over every string.

Why it happens

Case may encode sentence starts, proper names, acronyms, brands, honorifics, and component genre at once. If authors, translation tools, and clients each transform it independently, adjacent surfaces drift and automatic conversion damages brands, internal capitals, accented letters, or language-specific mappings. Even title case disagrees about which words to capitalize across languages and style guides; English whitespace rules cannot simply be exported. Binding the rule to locale, content class, and component semantics separates editorial consistency from spelling that must remain intact.

Studying it

Inventory supported languages and components, then annotate a sample as compliant, legitimate exception, or unresolved. Measure reviewer agreement, erroneous transformations, recognition of hierarchy and names, and cross-channel drift. Compare sentence and title case only within one language, natural copy, and constant hierarchy, controlling length, font, familiarity, and platform history rather than generalizing English results. Evaluate automated checks on a benchmark containing brands, acronyms, mixed scripts, diacritics, and dynamic variables.

Where it stops holding

Brands, product names, acronyms, code, commands, file names, and user-authored content may need literal preservation; proper-name casing follows its language and authoritative spelling. All caps can encode a scoped industry or state convention, but should not become default emphasis. Caseless scripts still need typographic hierarchy, just not letter conversion. Display casing must not silently change search, sort, or identity matching, which require separate normalization and collation rules.

Applying it

• Define a locale × component matrix with convention, examples, owner, and version. Never run an English title-case converter over every translation.
• Register scoped exceptions for brands, acronyms, code, proper names, user content, and terms with preserved case. Do not let container CSS or runtime functions rewrite inserted variables blindly.
• Make authoring, TMS, components, notifications, and email templates consume the same rule version. Scan unexplained drift within equivalent components and route uncertain language mappings to native review.
• Regress real fonts, truncation, screen readers, and copy/paste. Inspect both presentation and source text so a visual transform does not corrupt accessible names, search keys, or input.

Related

• Same group: T1.06.2 End punctuation is usually omitted in short labels · T1.06.3 Mixing full-width and half-width punctuation breaks reading rhythm · T1.06.4 Exclamation marks need a budget
• Adjacent: S2.08.3 Case and diacritics affect collation results · T1.04.2 The glossary must cover interface, docs, and support
• Search terms: capitalization style · sentence case · locale-aware title case