Adding custom dictionaries for Nuance Vocalizer

Last Updated : Jun 05, 2026 |

An application that uses the Nuance Vocalizer server can use a custom dictionary. You can create as many custom dictionaries as you require. You can pass the dictionary as a vendor specific parameter switts.ssftrs_dict_enable or define the dictionary using parameter dictionaries in the Nuance Vocalizer configuration file baseline.xml.

Procedure

  1. Create the custom dictionaries, as described in the Nuance Vocalizer documentation. Nuance Vocalizer doesn’t support text-based dictionary format (DCT or TDC files) anymore, only binary user dictionary format, BDC or DCB files, is supported. The binary dictionary format has also changed.
  2. Convert the old text format dictionary (.dct or .tdc) to the new Vocalizer text format dictionary (.txt) with the following command:

    dictmigrate –i <old-dictionary> -o <new_dictionary>

    For example:

    dictmigrate -i DictionaryName.dct –o DictionaryName.txt

    Note:

    Skip this step if you’ve already created a new text format dictionary.

  3. Compile text format dictionary (.txt) to binary format dictionary, .bdc or .dcb, with the following command:

    dictcpl –o <BinaryFilename.bdc> <TextName.txt>

    For example:

    dictcpl -o DictionaryName.bdc DictionaryName.txt

If the user dictionary will be accessed from the application server through HTTP, you must map the dictionary extensions that you are using to the appropriate MIME type.

  1. On each Nuance Vocalizer HTTP server, open the mime.types file.

    The default file location on Linux is in the /etc/ directory. The default locations on Windows are:

    • For a 32 bit system:

      C:\Program Files\Apache Software Foundation\Apache2.2\conf

    • For a 64 bit system:

      C:\Program Files (x86)\Apache Software Foundation\Apache2.2\conf

  2. Add the following lines to mime.types to associate text and binary dictionaries with the correct file extensions:

    application/octet-stream            bdc

    application/octet-stream            dcb

    application/octet-stream            dct

    application/octet-stream            tdc

  3. Save and close the file.
  4. Upload the custom dictionaries as described in the Nuance Vocalizer documentation.

Next Steps

Associate the dictionary with the application.