Enable Multilingual Spell Check in Collabora Online CODE

To spell-check more than one language in Collabora Online, add each required language code to the CODE container’s dictionaries setting, restart the container, and assign the correct language to each text passage. Both sides matter: the server must make the dictionaries available, and the document must mark English, French, or another passage with its language. Adding a language to the container alone does not automatically identify every language in a document.

What has to be configured?

There are two separate settings to consider:

• Server dictionaries: The CODE Docker image enables a limited dictionary list by default. Its dictionaries environment variable changes the list of dictionary languages CODE configures. Collabora’s 25.04 SDK manual documents space-separated language codes, optionally followed by a country code, and notes that limiting the list helps avoid unnecessary resource use and startup work.
• Document language: Collabora uses the language assigned to text to select the spelling dictionary. A document can contain different languages in different selections or paragraphs, so each passage should be tagged correctly.

For example, a document with English (United States) and French passages needs both codes enabled on the server, and its English and French text must carry the corresponding language setting. A user interface language or keyboard layout is not a substitute for either setting. See the Collabora Online 25.04 SDK manual and the Collabora help topic on selecting a document language.

Configure language dictionaries in CODE Docker

Docker Compose example

Add the desired locale codes as a space-separated string in the Collabora service’s environment. This example keeps the list to US English, UK English, and French:

services:
  collabora:
    image: collabora/code
    restart: unless-stopped
    environment:
      dictionaries: "en_US en_GB fr_FR"
      domain: "cloud\.example\.com"
      username: "collabora_admin"
      password: "replace-with-a-long-unique-password"
    ports:
      - "127.0.0.1:9980:9980"

Replace the domain pattern, credentials, image tag, and port mapping to match your deployment. Keep the existing reverse proxy and Nextcloud connection settings; this snippet only illustrates where the dictionary list belongs. If you already use a Compose file, edit the existing Collabora service instead of creating a second container.

The language codes above follow the codes documented by Collabora, where a locale can include a country code. Use codes matching the document languages your users need. Do not assume every possible code has a usable dictionary in every CODE image: the SDK manual describes changing the configured list, while the installed build and its dictionaries still determine what is actually available. Check the documentation for the CODE image version you run before adding less common locales.

Apply the change

1. Back up or commit the current Compose file so you can revert the change.
2. Update the dictionaries value with only the languages your users need. Preserve the other Collabora environment variables.
3. Recreate the service so Docker passes the updated environment into the container. For a Compose deployment, run docker compose up -d --force-recreate collabora from the directory containing the Compose file.
4. Check startup output with docker compose logs --tail=100 collabora. Look for startup or dictionary-loading errors; do not treat a successful container status alone as proof that a particular dictionary is installed.

If your deployment uses docker run instead, update its -e dictionaries="en_US en_GB fr_FR" argument and recreate that container with the same network, volume, proxy, and security options. Changing the environment on a running container does not change the environment it was started with.

Assign a language to each passage

After the server is ready, open a document in Nextcloud and select the text whose language you want to check. In Collabora’s language controls, choose the language for the selection or paragraph; for a document that is all one language, use the option that applies the language to all text. The command labels can differ slightly between releases and screen layouts, but the key is to set the document text language rather than only changing the interface language. Collabora’s help explains that a document language determines the dictionary used for spell-checking, thesaurus, and hyphenation.

For a mixed-language document, apply the language in chunks. For example, select the French paragraph and set French (France), then select the English paragraphs and set English (United States). If new text inherits the wrong language, place the cursor in that paragraph and change its language before typing, or select and retag the text afterward. A misspelled-looking word may simply be text marked with the wrong language.

Spell-check may also be disabled for a selection or language. In Collabora’s language menu, “None” excludes selected text from spell-checking and hyphenation. If the text has the correct language but receives no spelling marks, verify spell-check status for that language and inspect whether the selection is excluded. The Collabora Language help page describes the language choices and the “None” option.

Quick checks when a language is missing

Nextcloud’s administration manual describes the Collabora server URL under the Office configuration. Keep that integration setting separate from the dictionary change; if the connection already worked before, you normally should not need to change it for spell-check languages. Refer to the Nextcloud Office configuration documentation.

Verify the result in a real document

Create or open a test document and type a deliberately misspelled word in each enabled language. Set each sample passage to its intended language, then confirm that the spell-check marks the intentional error. Also type a correctly spelled word in each language to make sure it is not being treated as foreign text. Repeat with a second user if language availability differs by account or document.

If a language still fails, reduce the test to one locale at a time, check CODE logs, and compare the code against the documentation for the exact image version. Collabora’s default dictionary allowlist and image contents can change between releases; the 25.04 manual’s documented defaults should not be assumed for every later tag. Once spelling works in each explicitly tagged passage, retain the smallest language list that meets your users’ needs.