How to validate accessibility across multiple locales

By Ashok Kumar Yadav, Senior Software Engineer & Accessibility Architect   <https: www.ashokkumaryadav.com=""> <https: www.linkedin.com="">

Accessibility validation is hard enough on a single site. Across 15 or more locales, it becomes a systems problem.

Most teams treat localization and accessibility as separate workstreams. Localization handles translation, date formats, and currency. Accessibility handles contrast, keyboard navigation, and screen reader support. The two rarely talk to each other — and that gap is where failures hide.

This guide covers how to build a validation approach that treats both as a shared concern from the start.

Understand what changes across locales

Before setting up tooling, it helps to know which accessibility properties are actually locale-sensitive.

Some are obvious. Text length changes with translation — a German string can be 30% longer than its English equivalent, breaking fixed-width containers and truncating content that screen readers depend on. Right-to-left (RTL) languages like Arabic and Hebrew reverse the visual and logical order of the page. A component that passes keyboard navigation checks in English may fail in an RTL context if dir attributes are missing or incorrectly scoped.

Others are less obvious. Number and date formats affect how assistive technology reads values aloud. A date written as 04/05/2024 is read differently depending on locale conventions, and if the underlying markup does not include a machine-readable format via the time element, screen readers may announce it ambiguously. Currency symbols, phone number formats, and measurement units carry similar risks.

Start by auditing your content types — not just your components — and mapping which ones have locale-specific rendering behavior.

Build a locale matrix

A locale matrix is a structured list of your supported locales paired with the specific accessibility risks each one introduces. It does not need to be complex. A spreadsheet or a markdown table works.

For each locale, note:

–        Text direction (left-to-right or right-to-left).

–        Script type (Latin, CJK, Arabic, Devanagari, etc.).

–        Known translation length variance relative to your source language.

–        Any regulatory requirements specific to that region (for example, the European Accessibility Act, which applies across EU member states).

This matrix becomes the foundation for deciding which locales need manual testing, which can be covered by automation, and where your highest risk surface area is.

Automate what you can — and know its limits

Automated tools like Deque Axe, IBM Equal Access Checker, and Lighthouse catch a reliable subset of issues: missing alt attributes, insufficient color contrast, form labels, heading order. These checks are locale-agnostic in most cases, which means they can run in your CI/CD pipeline against every locale variant without manual intervention.

The practical approach is to run automated checks against a representative URL for each locale on every deploy. You can do this with a script that loops through your locale list and passes each URL to your testing tool of choice.

Example: Axe + Node.js locale loop

const { AxePuppeteer } = require('@axe-core/puppeteer');

const puppeteer = require('puppeteer');

const locales = ['en-US', 'de-DE', 'ar-AE', 'ja-JP'];

const baseUrl = '<https: example.com="">';

(async () => {

  const browser = await puppeteer.launch();

  for (const locale of locales) {

    const page = await browser.newPage();

    await page.goto${baseUrl}/${locale}/);

    const results = await new AxePuppeteer(page).analyze();

    console.log${locale}: ${results.violations.length} violations);

    results.violations.forEach(v =>

      console.log - ${v.id}: ${v.description})

    );

    await page.close();

  }

  await browser.close();

})();

What automation will not catch: focus management issues introduced by RTL layout, screen reader announcement quality for translated strings, or touch target problems caused by text expansion. Those require manual testing.

Set up manual testing by locale tier

Not every locale needs the same level of manual testing. Group your locales into tiers based on traffic, regulatory exposure, and accessibility risk profile.

A practical three-tier structure:

Tier 1 — Full manual testing.

Your highest-traffic locales and any locale in a region with active accessibility regulation. Test with real assistive technology: NVDA or JAWS on Windows, VoiceOver on macOS and iOS, TalkBack on Android.

Tier 2 — Targeted manual testing.

Mid-tier locales where you test specific components that are known to vary by locale — date pickers, form validation messages, navigation patterns.

Tier 3 — Automated only.

Lower-traffic locales where automated checks run on every deploy, with manual testing triggered only when violations are detected.

Test right-to-left layouts explicitly

RTL validation deserves its own step in your process because the failure modes are different from left-to-right testing.

Check these specifically:

–        The dir="rtl" attribute is set on the html element (not just on individual elements), and it is driven by locale, not hardcoded.

–        Focus order follows the visual reading order of the page. Keyboard navigation that moves left-to-right in English should move right-to-left in Arabic.

–        Icons that imply direction — arrows, progress indicators, breadcrumb separators — are mirrored appropriately.

–        Modal dialogs and drawers open from the correct side.

–        Form error messages appear adjacent to the relevant field in the correct position for the text direction.

Test RTL locales with a native or fluent speaker when possible. Issues that look correct visually can be semantically wrong in ways that only surface during real use.

Handle text expansion proactively

Translation into German, Finnish, or Portuguese can increase string length by 20–40% compared to English source content. This causes truncation, overflow, and layout collapse — all of which can hide or break accessible elements.

Two approaches that work in practice:

Pseudolocalization — replacing source strings with expanded placeholder text during development, before real translations exist. Tools like the pseudolocale npm package generate strings 30–40% longer than the original, using characters outside the Latin alphabet, which surfaces both layout and encoding issues early.

Component length constraints — define maximum character counts in your component contracts and share them with your localization team. When translations exceed the limit, the component should handle overflow gracefully by wrapping rather than truncating, and that overflow behavior should be tested for accessibility.

Create a shared defect taxonomy

When you find accessibility issues across multiple locales, categorizing them consistently makes patterns visible. Without a shared taxonomy, the same underlying component defect gets logged fifteen times as fifteen separate bugs.

A simple taxonomy:

–        **Component-level — **A defect in the shared component itself, affecting all locales that use it.

–        **Locale-specific — **A defect that only appears in one locale due to translation content, text direction, or regional format.

–        **Integration — **A defect where the component is correct, but the locale context breaks it — for example, a correct date component receiving a malformed date string from the localization layer.

Tagging defects this way lets you route fixes correctly. Component-level defects go to the design system team. Locale-specific defects go to the localization team. Integration defects require both.

Document your validation coverage

At the end of each release cycle, produce a coverage report that shows:

–        Which locales were tested?

–        Which tier of testing was applied?

–        How many violations were found and resolved by locale?

–        Any known open issues and their associated risk level.

This document gives stakeholders an honest view of where gaps exist, which is more useful than a blanket accessibility statement. It also creates a baseline that makes regressions visible over time.

Accessibility validation across many locales is not a one-time audit. It is a repeating process that improves as your tooling, taxonomy, and team knowledge mature. Starting with automation in your pipeline and a clear manual testing tier structure gives you a foundation that scales — even as the number of locales grows.

Ashok Kumar Yadav, IEEE Senior Member, IAAP Member

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