Why a font substitutes glyphs in a bilingual document

You chose one font for a bilingual document, but some letters look different, shift position, or appear as empty boxes. This usually means the selected font cannot provide every character in the text, so the app uses another font for the missing glyphs.

Check which fonts are installed and whether they can preview your sample text with the Installed Fonts tool. Then check the document's font settings and the way it will be shared.

Check the font coverage

1. Open the Installed Fonts tool in Chrome or Edge on a computer. Other browsers may show a reduced version or no font list.
2. Enter a short sample containing both languages, including accented letters, punctuation, and any special symbols that appear in the document.
3. Preview the sample in the font you selected. Check whether the different scripts display consistently, and compare a few other installed fonts.
4. Return to the document and select a suspicious character. Check the font name shown for that character or text selection. Some editors apply a different font to only part of a line.

A font can cover the Latin alphabet but lack the characters used by another language. The document app then finds a fallback font, meaning a second font that supplies the missing character. This can happen one letter at a time, so the substitution may be easy to miss. For related examples, see why a font may display characters it does not contain.

What the result means

The sample changes style in the second language

The selected font likely lacks some characters in that script, or your document editor is applying a different font to that text. A fallback can have a different weight, size, or design, even when the paragraph appears to use one font. Try a typeface with coverage for both languages, or assign a matching font to each script.

Boxes or blank spaces appear in the sample

The browser cannot draw those characters with the font being previewed. The font may not include them, or the font file may be damaged or incomplete. Try another font with the needed script. If every font fails, check whether the characters were copied correctly and whether the operating system has support for that language installed.

The tool preview looks right, but the document does not

The font has the characters, but the editor may have assigned another font to a section, applied a character style, or used a document theme font. Select the affected text and inspect its font setting. Also check for local formatting that differs from the surrounding paragraph.

The document looks right on your computer but changes elsewhere

The other computer may not have the font installed. Some file formats can include embedded fonts, but not every font license allows embedding, and some editors or export settings do not include them. Export a PDF with fonts embedded when your software offers that option, then open the PDF on another device to check it.

How to fix it

1. Select the affected text. In the document editor, highlight a character that looks wrong and inspect the font shown for that selection. Apply the intended font to the full affected word or script, not just the paragraph.
2. Choose a font with both scripts. Use the Installed Fonts preview to compare the actual languages and symbols in your document. A font described as supporting a language may still omit uncommon characters, so test your real text.
3. Check the document's language and style settings. Make sure the text is marked with the correct language, especially if the editor applies language-specific fonts or proofing rules. Look for character styles and theme settings that may override the font you selected.
4. Install the required font. On Windows 11, open Settings › Personalization › Fonts to manage installed fonts, or install a trusted font file from its context menu. On a Mac, open Font Book, then use File › Add Fonts to Current User. Close and reopen the document editor after installation.
5. Check the exported file. If you are sharing a PDF, use the export option that embeds fonts when available. Reopen the exported file on another device or in a separate PDF viewer. If the text still changes, use a font that permits embedding or share the document in a format that preserves its font requirements.

Installing a font only helps if the file contains the needed glyphs. Check that the font comes from a trusted source and is intended for your operating system. If it is a work or school computer, an administrator may need to approve installation.

Why bilingual text can be more complicated

Some writing systems need more than a set of individual letter shapes. Characters may join, change shape based on their position, or combine with marks above or below them. The document app and font must handle those rules correctly. If letters appear separated, misplaced, or reordered rather than simply different in style, try another font and check the editor's language and text direction settings.

Font names can also be confusing. The name shown in an editor may not match the font file name, and a family may include separate regular, bold, and italic files with different character coverage. For a multilingual document, check the exact style you are using, not only the general family name. See how to check fonts for multilingual text for a broader coverage check.

The Installed Fonts tool checks fonts available to your browser on this device. It cannot guarantee that another person's computer has the same fonts or that a document editor will render them identically.