Latin Extended Font Support

Language Coverage Requirements

Each language has specific characters that are non-negotiable. Missing a single character does not just break that word — it typically falls back to an entirely different font family, disrupting visual consistency. The table below lists the minimum character requirements for each major European language and Vietnamese.

Hungarian adds ő and ű (double acute accent, U+0151 and U+0171) to the basic Extended-A set. Lithuanian uses ą ę į ų (ogonek below vowels) plus ė (dot above) and ū (macron). Latvian uses ā ē ī ū (macron) and ģ ķ ļ ņ ŗ (cedilla below). All three Baltic languages are covered by Latin Extended-A through U+017F.

Testing Font Character Support

The most reliable test is rendering real-language text in the font and looking for tofu — the empty rectangular boxes that appear when a glyph is missing. Each missing character triggers a fallback to the next font in your stack, potentially changing weight, width, and colour mid-word. Copy the test strings below into your browser's developer tools or a live preview environment.

Beyond visual inspection, use programmatic coverage checks. Our Font Analyzer reports which Unicode code points are present in a font file, so you can verify coverage against your target character set before deploying. Third-party tools like Wakamai Fondue and FontDrop also display Unicode coverage tables without requiring font upload to a remote server.

Subsetting for Latin Extended

The CSS unicode-range descriptor in @font-face enables selective font loading: the browser only downloads a font file when a character in that range actually appears on the page. This is the foundation of progressive Latin loading — deliver the most common characters first, then extended characters on demand.

Progressive loading: Basic Latin first

/* Tier 1: Basic Latin — loads immediately, always needed */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/fonts/inter-latin-basic.woff2') format('woff2');
  unicode-range: U+0020-007F, U+00A0-00FF; /* Basic + Latin-1 Supplement */
}

/* Tier 2: Latin Extended-A — loads when Polish, Czech, Turkish etc. appear */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/fonts/inter-latin-ext-a.woff2') format('woff2');
  unicode-range: U+0100-017F; /* Latin Extended-A */
}

/* Tier 3: Latin Extended-B — loads for Romanian comma-below ș ț */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/fonts/inter-latin-ext-b.woff2') format('woff2');
  unicode-range: U+0180-024F; /* Latin Extended-B */
}

/* Tier 4: Latin Extended Additional — loads only for Vietnamese */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/fonts/inter-latin-ext-additional.woff2') format('woff2');
  unicode-range: U+1E00-1EFF; /* Latin Extended Additional */
}

Full European coverage — single unicode-range

If you prefer a single subset file for all European languages (excluding Vietnamese), use this consolidated range. It adds roughly 15–25 KB compared to Basic Latin alone, well worth the coverage.

/* All European Latin — one file, all accents */
@font-face {
  font-family: 'YourFont';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/fonts/yourfont-latin-all.woff2') format('woff2');
  unicode-range:
    U+0020-007F,  /* Basic Latin */
    U+00A0-00FF,  /* Latin-1 Supplement */
    U+0100-017F,  /* Latin Extended-A */
    U+0180-024F,  /* Latin Extended-B (Romanian ș ț) */
    U+0300-036F,  /* Combining Diacritical Marks (for dynamically composed text) */
    U+2000-206F,  /* General Punctuation (em dash, curly quotes, etc.) */
    U+20A0-20CF;  /* Currency Symbols (€, £, ¥) */
}

Use our Font Subsetter to generate these split files from any TTF or OTF. The tool accepts a unicode-range string directly and outputs a WOFF2 file containing exactly those glyphs. Use our Unicode Range Generator to build custom range strings for any combination of languages.

Common Missing Characters

Font designers working primarily for Western European markets routinely omit certain Extended-A and Extended-B characters from their glyphsets. The omissions follow a predictable pattern: characters with complex diacritics that sit below the baseline (which require careful sidebearing and kerning work) are more often skipped than those with marks above the x-height.

Font Recommendations by Latin Coverage

The table below rates popular web fonts against Latin coverage tiers. Coverage is verified against the fonts' published character maps and Google Fonts coverage data. Checkmarks indicate full, intended support with properly designed glyphs — not fallback or approximated characters.

✓ = full coverage with intentional glyph design. ~ = partial coverage (most characters present but some edge cases missing). ✗ = not covered. Roboto and Open Sans cover Romanian comma-below for common characters but may miss some extended Latin-B additions. Lato's Vietnamese support is partial — basic tone marks work but some stacked diacritic combinations (e.g., ặ, ệ, ộ) fall back to the system font.

Vietnamese: The Most Demanding Latin Script

Vietnamese is written entirely in the Latin script — a legacy of 17th-century Portuguese missionaries who created Chữ Quốc Ngữ (National Language Script). Despite using Latin letters, Vietnamese typography is fundamentally different from European Latin typography because it stacks diacritics: a vowel can carry both a base modification (circumflex, breve, or horn) and a tone mark (acute, grave, hook, tilde, or dot below), resulting in characters like ậ (a + circumflex + dot below) and ợ (o + horn + hook below).

The total number of distinct precomposed Vietnamese characters in Unicode is 134, all concentrated in the Latin Extended Additional block (U+1E00–1EFF). This block is the single most frequently omitted block in Latin fonts — it adds roughly 8–15 KB to a WOFF2 file, a cost many font designers consider unjustified for a non-European market.

The consequence for Vietnamese text rendering without proper font support is severe: not just missing box characters, but complete failure to display tone-marked vowels — making the text phonetically ambiguous and often semantically incorrect. Vietnamese relies on tone marks to distinguish words that are otherwise identical in consonant and vowel structure.

@font-face {
  font-family: 'YourFont';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/fonts/yourfont-vietnamese.woff2') format('woff2');
  unicode-range:
    U+0102-0103,  /* ă Ă */
    U+0110-0111,  /* đ Đ */
    U+0128-0129,  /* ĩ Ĩ */
    U+0168-0169,  /* ũ Ũ */
    U+01A0-01A1,  /* ơ Ơ */
    U+01AF-01B0,  /* ư Ư */
    U+1EA0-1EF9,  /* full Vietnamese precomposed block */
    U+20AB;       /* ₫ Vietnamese Dong sign */
}

For production Vietnamese sites, Inter, Noto Sans, Source Sans 3, and IBM Plex Sans all provide reliable coverage. Test with the sentence Tiếng Việt có sáu thanh điệu: ngang, huyền, sắc, hỏi, ngã, nặng — this string exercises all six tones across multiple vowel families and will immediately reveal any missing glyphs.