Configure n-gram models

N-gram models improve spell checking suggestion quality.

N-gram models use language-specific model files stored in the AppServer resources directory.

The default location is <WebSpellChecker_installation_path>/AppServer/Resources/. The actual path is controlled by ResourcesDir in AppServerX.xml. See AppServer parameters.

N-gram models are configured via the NgramPrioritization tag in AppServerX.xml. It is nested under the Hunspell spell engine options for a CheckKit.

All supported n-gram models are enabled by default.

Each n-gram model uses roughly the same amount of RAM as its file size on disk. Model sizes are listed in the table below.

Installation

Model files are downloaded during installation.

After download, the installer places the models into the AppServer resources directory. The spell engine loads them from the path configured in NgramPrioritization (for example, en/en_ngram_model.bin).

If your server has no Internet access, see Manually downloading resources (offline installation).

Available n-gram models

Language	Supported language IDs	Model file	Size
English	en_US, en_GB, en_CA, en_AU, en_NZ, en_ZA	en_ngram_model.dat	80 MB
German	de_DE, de_CH, de_AT	de_ngram_model.dat	78 MB
Spanish	es_ES	es_ngram_model.dat	100 MB

Change n-gram settings (enable/disable)

1. Open <WebSpellChecker_installation_path>/AppServer/AppServerX.xml.

2. Find the NgramPrioritization tag for the language you need.

3. Change the Enabled attribute:

   • Set Enabled="true" to enable n-gram prioritization.

   • Set Enabled="false" to disable n-gram prioritization.

Example:

<NgramPrioritization Enabled="true" Path="en/en_ngram_model.bin"/>

1. Save the file.

Restart AppServer to apply changes in AppServerX.xml.

To restart: stop the application, then start it again.

Use Main AppServer commands.

Error: failed to load n-gram model

If n-gram prioritization is enabled but the model file is missing, AppServer logs an error. Example:

02/16/26:10:28:15.512    #23:0    Subsystem_General    Error    PerformRequest. command: check, exception: Failed to load n-gram model. Failed to open n-gram model for reading: Resources/en/en_ngram_model.bin Model path: en/en_ngram_model.bin, code: 2039360264792508448

This error usually means the model file is missing in the AppServer resources directory.

If the installation was done without downloading resources, re-run the installation with internet connection, or use the offline download procedure.