SpVoice Word event (SAPI 5.3)

Speech API 5.3
Microsoft Speech API 5.3

Object: SpVoice (Events)

Word Event

The Word event occurs when the text-to-speech (TTS) engine detects a word boundary while speaking a stream for the SpVoice object.

     StreamNumber As Long,
     StreamPosition As Variant,
     CharacterPosition As Long,
     Length As Long


The stream number which generated the event. When a voice enqueues more than one stream by speaking asynchronously, the stream number is necessary to associate an event with the appropriate stream.
The character position in the output stream at which the word begins.
The character position in the input stream one character before the start of the word. In the case of the first word in a stream, this parameter is zero.
The length of the word in the input stream.


The following Visual Basic form code demonstrates the use of the Word event. To run this code, create a form with the following controls:

  • A command button called Command1
  • A text box called Text1
  • Set the HideSelection property of Text1 to False

Paste this code into the Declarations section of the form.

The Form_Load procedure puts a text string in Text1 and creates a voice object. The command1_Click procedure calls the Speak method. This will cause the TTS engine to send the Word event to the voice; the Word event code will use the event parameters to highlight the word associated with the event.

Option Explicit

Public WithEvents vox As SpeechLib.SpVoice

Private Sub Command1_Click()

    vox.Speak Text1.Text, SVSFlagsAsync

End Sub

Private Sub Form_Load()

    Set vox = New SpVoice
    Text1.Text = "This is some text in a textbox."

End Sub

Private Sub vox_Word(ByVal StreamNumber As Long, ByVal StreamPosition As Variant, _
                     ByVal CharacterPosition As Long, ByVal Length As Long)

    ' In order to show this selection,
    ' the Text1.HideSelection property must be False!

    Text1.SelStart = CharacterPosition
    Text1.SelLength = Length

End Sub