Creating a lexicon file

Creating a new lexicon file

Use the following steps to create a new lexicon file:

1. If you do not have a project where your lexicon file resides, create a voice project by navigating to File > New > Voice Project . Otherwise, select the desired voice project in the Navigator.
2. Optional: If your project will be used for web deployment, you can create a subfolder within the WebContent folder in which to place your lexicon file. To do this, select File > New > Other > General > Folder and type the folder name. Folders are optional containers for organizing files within a voice project.
3. In the Navigator view, select (highlight) the folder you created for your lexicon file, and from the File menu, select New > LMXL File.
4. The New File wizard appears and guides you through the steps for creating a new grammar file. Select how you want to create it, from scratch, resulting in an empty file, or with DTD assistance.
5. Click Next.
6. In the File Type box, select the type of file:

   Recognition

   Creates pronunciations for the speech recognition engine using International Phonetic Alphabet (IPA) phonologies. Select this option when creating grammars with words that you expect users to say when interacting with the application. This is the default selection.

   Synthesizer (Text to Speech)

   Creates pronunciations for the synthesized speech (TTS engine) using Symbolic Phonetic Representations (SPR) phonologies. Select this option when creating grammars with words that the synthesized voice will say to users.

7. Type your new file name. The default extension for a lexicon file is .lxml, however, you can also use the extensions .lexml and .pls.
   Tip: Filenames are case-sensitive. The lexicon browser URLs should be case-consistent to avoid duplicate loads.  For example, do not name one file A.lxml and another a.lxml.
8. Optional: Click Advanced (available in some installed products) to reveal or hide a section of the wizard used to create a linked file. Check the Link to file in the file system check box if you want the new file to reference a file in the file system. In the field below the check box, enter a file path or the name of a path variable. Click Browse to locate a file in the file system. Click Variables if you want to use a path variable to reference a file system file.
9. Click the Finish button and the Lexicon editor launches your file with the basic <lexicon> tag.

Adding words and pronunciations

In the lexicon file, you will add all the words that users could say while interacting with the application. Each word must also include phonetic pronunciation understood by the speech recognition engines.

The toolkit provides a built-in Pronunciation Builder that automatically creates a phonology for the words you add. To do this:

1. In the Source tab of the Lexicon editor, right-click, and click Compose Pronunciation.
2. In the Pronunciation Builder, type a word that you want added to the grammar, and click Get Default Pronunciation.
   Tip: See the online help for Pronunciation Builder information for details on using the Pronunciation Builder window.
3. When you click Apply or OK, the word and phonology are added to the lexicon file with the correct tags.
4. Continue to add the pronunciations, one word at a time. You can add multiple pronunciations for the same word, if needed.
5. When you finish, save your file.

Importing or converting existing pronunciation files

If you have existing pronunciation pool files (.pbs) for speech recognition or exception dictionary files (.eci) for speech synthesis, you can import them into a lexicon file.

1. With a lexicon file open in the editor, right-click, and click Import pronunciation file.  
2. Follow the instructions to import the words and phonologies in the pool file (if you are importing into a Recognition lexicon) or exception dictionary (if you are importing into a Synthesizer lexicon) into the lexicon file.  
3. Continue to add or modify pronunciations, as needed, and save the file.

Alternatively, you can convert an existing pronunciation file into a lexicon file:

1. Right-click a .pbs or .eci file in the Navigator, and click Convert to Lexicon File.
   Note: To convert multiple files (of the same file type) in one operation, press the Ctrl key, click the files, and then right-click the group.
2. The new file is created with the same file name and the extension .lxml. If the name already exists in the voice project, you can choose to overwrite the file or cancel the operation.
3. The words and pronunciations in the new file are automatically converted to the lexicon markup language, and the file is added to the voice project. Words that had errors in the original file are ignored in the converted file.

Phonology examples

Although the speech recognition and TTS engines use a common lexicon format, the lexicons themselves are not common, and there are significant differences in the alphabets used by the two systems.

Speech recognition phonology

The following sample code demonstrates the format and the features that are supported, such as multiple pronunciations per word, pronunciations specified as phone strings or sounds-like spellings, alternative spellings, case-sensitive or case-insensitive spellings, and proprietary phonetic alphabet support. The Lexicon editor adds the tag content (words and pronunciations) to the labels displayed in the Outline view, and displays the first spelling within the lexeme at the lexeme level of the tree structure, for easier traversal through the file.

<?xml version="1.0" encoding="UTF8"?>
<!DOCTYPE lexicon PUBLIC "-//com/ibm/speech/grammar/lexicon//DTD Lexicon 1.0//EN" 
"ibmlexiconml.dtd">

<lexicon version="1.0" xml:lang="en-US" alphabet="x-ibmasr" case-sensitive="false">

  <import uri="sourcelexicon.lxml"/>
 <lexeme>
    <spelling>preferred</spelling>
    <phoneme>P R AX F ER DD</phoneme>
    <phoneme>P R IX F ER DD</phoneme>
  </lexeme>
 <lexeme>
     <spelling>colour</spelling>
     <spelling>color</spelling>
     <phoneme>K AH L AXR</phoneme>
 </lexeme>
 <lexeme>
    <spelling>IEEE</spelling>
    <sounds-like>I triple E</sounds-like>
  </lexeme>
</lexicon>

TTS phonologies

The text-to-speech (TTS) engine supports the IPA alphabet and the SPR alphabet. The SPR alphabet will be referred to as x-ibmtts<lang> (for example, "x-ibmttsus", where "us" is US English).

For details on the SPR alphabet and the TTS phonologies, see the IBM Text-to-Speech SSML Programming Guide, (tts_ssml.pdf) in the online help.

The following example demonstrates the format and the features that are supported:

<?xml version="1.0" encoding="UTF8"?>
<!DOCTYPE lexicon PUBLIC "-//com/ibm/speech/grammar/lexicon//DTD Lexicon 1.0//EN" 
"ibmlexiconml.dtd">

<lexicon version="1.0" xml:lang="en-US" alphabet="x-ibmtts" case-sensitive="true">

  <import uri="sourcelexicon.lxml"/>                 
 <lexeme>
    <spelling>preferred</spelling>
    <phoneme>.0prI.1fxrd</phoneme>
    <phoneme>.0pri.1fxrd</phoneme>
  </lexeme>
 <lexeme>
     <spelling>colour</spelling>
     <spelling>color</spelling>
     <phoneme> .1kH.0lxr </phoneme>
 </lexeme>
 <lexeme>
    <spelling>IEEE</spelling>
    <sounds-like>I triple E</sounds-like>
  </lexeme>
</lexicon>

The TTS engine uses the first pronunciation when multiple pronunciations for a given word are specified. If the lexicon is not case-sensitive, add an entry for each spelling: the capitalized and the lower-case version.