Brief summary
If I currently try to load the sapi4 synth in nvda 2026.1, the synth fails to load. This appears to line up with something about lack of pitch handling on the sapi4 voice, since the sapi4 voice that loads when nvda did properly load the synth was a rare example of one that doesn't support rate and pitch control. This issue did not happen in any nvda 2025 releases, and only started in 2026 ones.
Steps to reproduce
- Start NVDA
- enter the synthesizer dialog (nvda ctrl s)
- if installed, attempt to select sapi4
Actual behavior
if the sapi4 voice that is selected by default as the driver is loaded has no pitch control, the loading of the synth will fail and the fall back logic runs, returning to the previously loaded synth driver. I'm unsure what happens if you can load it successfully, then switch to a voice without pitch control.
NVDA+ctrl+s
Select Synthesizer dialog
Synthesizer: combo box Microsoft Speech API version 5 (64 bit) collapsed Alt+ s
up arrow
Microsoft Speech API version 5 (32 bit)
up arrow
Microsoft Speech API version 4
enter
Synthesizer Error dialog Could not load the sapi4_32 synthesizer.
OK button
pressed
Select Synthesizer dialog
Synthesizer: combo box Microsoft Speech API version 4 collapsed Alt+ s
escape
Expected behavior
all properly configured sapi4 voices should be available, and the synth driver should not fail to load.
NVDA logs, crash dumps and other attachments
nvda with sapi4 synth change attempt.log
NVDA type
installed copy
NVDA version
2026.1 and 2026.1.1 (2026.1.1.55980)
Have you tried any other versions of NVDA? If so, please report their behaviors.
earlier versions including the last major versions of nvda 2025 do properly load the synth driver with the same voice selected on sapi4.
Windows version
Windows 11 25H2 (AMD64) build 26200.8457
Name and version of other software in use when reproducing the issue
loquendo tts engine version 7 (sapi4 synth installed when the error happens). Voices from this engine in sapi4 happen not to support rate and pitch, even though the sapi5 ones do.
Other information about your system
No response
Does the issue still occur after restarting your computer?
I have restarted my computer and the issue still occurs
If NVDA add-ons are disabled, is your problem still occurring?
I have restarted NVDA with add-ons disabled and the issue still occurs
Does the issue still occur after you run the System Accessibility Repair Tool (COM Registration Fixing Tool in older versions) in NVDA's tools menu?
I have run the System Accessibility Repair Tool and the issue still occurs
Brief summary
If I currently try to load the sapi4 synth in nvda 2026.1, the synth fails to load. This appears to line up with something about lack of pitch handling on the sapi4 voice, since the sapi4 voice that loads when nvda did properly load the synth was a rare example of one that doesn't support rate and pitch control. This issue did not happen in any nvda 2025 releases, and only started in 2026 ones.
Steps to reproduce
Actual behavior
if the sapi4 voice that is selected by default as the driver is loaded has no pitch control, the loading of the synth will fail and the fall back logic runs, returning to the previously loaded synth driver. I'm unsure what happens if you can load it successfully, then switch to a voice without pitch control.
NVDA+ctrl+s
Select Synthesizer dialog
Synthesizer: combo box Microsoft Speech API version 5 (64 bit) collapsed Alt+ s
up arrow
Microsoft Speech API version 5 (32 bit)
up arrow
Microsoft Speech API version 4
enter
Synthesizer Error dialog Could not load the sapi4_32 synthesizer.
OK button
pressed
Select Synthesizer dialog
Synthesizer: combo box Microsoft Speech API version 4 collapsed Alt+ s
escape
Expected behavior
all properly configured sapi4 voices should be available, and the synth driver should not fail to load.
NVDA logs, crash dumps and other attachments
nvda with sapi4 synth change attempt.log
NVDA type
installed copy
NVDA version
2026.1 and 2026.1.1 (2026.1.1.55980)
Have you tried any other versions of NVDA? If so, please report their behaviors.
earlier versions including the last major versions of nvda 2025 do properly load the synth driver with the same voice selected on sapi4.
Windows version
Windows 11 25H2 (AMD64) build 26200.8457
Name and version of other software in use when reproducing the issue
loquendo tts engine version 7 (sapi4 synth installed when the error happens). Voices from this engine in sapi4 happen not to support rate and pitch, even though the sapi5 ones do.
Other information about your system
No response
Does the issue still occur after restarting your computer?
I have restarted my computer and the issue still occurs
If NVDA add-ons are disabled, is your problem still occurring?
I have restarted NVDA with add-ons disabled and the issue still occurs
Does the issue still occur after you run the System Accessibility Repair Tool (COM Registration Fixing Tool in older versions) in NVDA's tools menu?
I have run the System Accessibility Repair Tool and the issue still occurs