Internationalization, Localization & Accessibility

By the end, you can

• Distinguish i18n, l10n, and a11y and explain which must come first in the development process.
• Explain what a locale is and why language alone is insufficient for formatting decisions.
• Use Intl.DateTimeFormat and Intl.NumberFormat to format dates and numbers for a given locale.
• Apply CLDR plural rules and explain why appending "s" fails outside English.
• Set up RTL layout correctly using dir="rtl" and CSS logical properties.
• Identify the four WCAG POUR principles and give a concrete example of each.
• State the WCAG AA minimum contrast ratio for normal text.
• Explain why semantic HTML elements are preferable to styled divs for interactive controls.
• Apply the First Rule of ARIA and describe when ARIA is actually appropriate.
• Write correct alt text for meaningful and decorative images.
• Describe the three layers of accessibility testing and why manual testing cannot be skipped.