Make Windows Mobile Text-to-Speech voices available for System.Speech.Synthesis
Okay, thanks to reddit comment from a 'Pessimist__Prime' (details below) I found a way to enable some more voices on my (Win 8+) machine, without installing anything else.
Under text-to-speech settings I could see various voices (such as "Microsoft James Mobile") but these voices were not visible when calling synth.GetInstalledVoices (where synth = new System.Speech.Synthesis.SpeechSynthesizer()).
However, by copying some details from:
HKLM:\software\Microsoft\Speech_OneCore\Voices\Tokens
to both these locations:
HKLM:\SOFTWARE\Microsoft\Speech\Voices\Tokens
HKLM:\SOFTWARE\WOW6432Node\Microsoft\SPEECH\Voices\Tokens
...all of the installed voices became available.
Here's the script for performing the copy, provided by Pessimist__Prime at reddit:
$sourcePath = 'HKLM:\software\Microsoft\Speech_OneCore\Voices\Tokens' # Where OneCore voices live
$destinationPath = 'HKLM:\SOFTWARE\Microsoft\Speech\Voices\Tokens' # For 64-bit apps
$destinationPath2 = 'HKLM:\SOFTWARE\WOW6432Node\Microsoft\SPEECH\Voices\Tokens' # For 32-bit apps
cd $destinationPath
$listVoices = Get-ChildItem $sourcePath
foreach($voice in $listVoices)
{
$source = $voice.PSPath #Get the path of this voices key
copy -Path $source -Destination $destinationPath -Recurse
copy -Path $source -Destination $destinationPath2 -Recurse
}