A square box where a character should be does not necessarily mean the translation lost a word. The character may be present while the selected font cannot draw it. Conversely, changing fonts will not repair text that is missing or corrupted in the file.
For multilingual EPUBs, separate three questions: is the right character stored, can the reader display it, and is the language identified correctly? Test those questions before translating the book again.
Check whether the character exists
Find a short passage with the problem. Note its chapter, surrounding words, and the missing character's position. Compare it with the original, including accents, punctuation, and any mixed scripts.
If your reader allows copying, paste the passage into a plain-text editor using a font that supports the script. If the correct character appears there, the reading application's font or rendering is a likely cause. If the same incorrect text appears everywhere, investigate the file's content or the earlier extraction instead.
This is a diagnostic clue, not proof. Some readers restrict copying or substitute characters during export. Keep the actual EPUB and compare the same passage in another reading system before drawing a conclusion.
Try a font that covers the script
Use the reader's typography settings to try a system font suitable for the language. Where the application offers a publisher-font override, compare the book's supplied styling with the reader's own fonts.
A Latin font may display ordinary English and still lack Greek, Arabic, Chinese, or less common accented characters. Mathematical notation can need different coverage again. Check both ordinary prose and the particular symbols that failed.
Avoid assuming that one font solves every script. A multilingual passage may involve fallback fonts and different rendering behavior. Changing type size can reveal clipped marks or line-height problems that were hidden at the default size.
Embedding a font is an EPUB editing decision, not an automatic repair. It requires a suitable font, permission to distribute it, and correct resource references. PDF Craft does not promise that every font can be embedded or that every reader will honor it.
Language tags and fonts do different jobs
Language declarations identify the language of publication metadata and content. They can help reading systems interpret text, including pronunciation and language-specific behavior. They do not add missing glyphs to a font.
The EPUB 3.3 specification defines publication metadata and content-document requirements. In an edited multilingual book, inspect the publication language and content declarations, including passages that switch languages. If you are not comfortable editing EPUB internals, ask someone familiar with the format to check a copy rather than modifying your only file.
For someone inspecting an unpacked EPUB, the OPF package metadata uses dc:language for the publication language. In the XHTML content, inspect lang and xml:lang on the document root and on passages in another language. For example, a French passage in an English chapter can be marked <span lang="fr" xml:lang="fr">Bonjour</span>. This is an illustrative file-level check, not a claim that PDF Craft automatically repairs every declaration. Work on a copy and validate any edits before opening it in your reader.
For a bilingual edition, verify that the original and translated passages are distinguishable and read in the intended order. Correct-looking text does not establish that language metadata is correct, and correct metadata does not establish translation accuracy.
Use a small cross-reader comparison
Test the same file and passage in two reading systems where possible. Keep the font and device conditions in your notes:
| Observation | What to investigate next |
|---|---|
| Works after changing the font | Script coverage or book styling |
| Works in one reader but not another | Reading-system support or rendering |
| Incorrect characters in all readers and copied text | Stored content or earlier recognition |
| Only marks or symbols clip at large size | Font metrics, spacing, or styling |
Do not compare different file versions without noticing. Name your source and result clearly, and confirm both readers opened the same download. A cached library copy can make a successful fix appear ineffective.
Check more than one sample before accepting a repair
After a font or file change, inspect headings, body paragraphs, italics, note markers, tables, and mixed-script passages. Enlarge the type and rotate or narrow the screen if that matches your reading setup. Confirm that the table of contents still leads to the right chapters.
PDF Craft offers translated or bilingual EPUB output; bilingual passages appear as original followed by translation. Download the result and use your preferred reader, with Desktop as an optional reading and organizing application. Typography checks remain useful whichever tool made the file.
For a broader file review, see translated EPUB compatibility checks. If you read on a tablet, follow the iPad reading workflow and test the difficult passage there. Fix the layer that failed—content, font, or reader—rather than rerunning translation by default.