[BUG] Voice switches accent

[jokerboy]

Library name and version

Microsoft.CognitiveServices.Speech

Describe the bug

When I use one of the voices that has a multilingual counterpart, for example 'en-US-AndrewNeural' & ''en-US-AndrewMultiLingualNeural', certain text causes the voice to switch accent.

Expected behavior

Audio will maintain the same accent during it's entirety.

Actual behavior

Audio switches between English, French, or Spanish depending on the text.

Reproduction Steps

using this code snippet causes the issue. When reproducing this, the values are as follows:

toPlay=

<speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xml:lang="en-US">
<voice name="en-US-AndrewNeural" xmlns="">
<prosody rate="0%" pitch="0Hz">Supreme Guest.
Deluxe Wash.</prosody>
</voice>
</speak>

voice.ShortName = 'en-US-AndrewNeural'
voice.Locale = 'en-US'

    var speechConfig = 
          SpeechConfig.FromSubscription(Settings.Local.AzureTTSSubscriptionKey,Settings.Local.AzureTTSServiceRegion);
    speechConfig.SpeechSynthesisVoiceName = voice.ShortName;
    speechConfig.SpeechSynthesisLanguage = voice.Locale;
    var speechSynthesizer = new SpeechSynthesizer(speechConfig);
    var toPlay = doc.ToString();
    var speechSynthesisResult = await speechSynthesizer.SpeakSsmlAsync(toPlay);

The audio is played, but the 'Deluxe Wash' is pronounced with a French accent.
Andrew-Voice-Bug.zip

Environment

Windows 11, Visual Studio 2022, CSharp .net 8.

[github-actions]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @robch.