[BUG] Read Aloud ignores Voice > Language = Portuguese (Portugal) and always uses a Brazilian Portuguese voice (Windows desktop)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet (closest is #85239, which is about German)
• [x] This is a single bug report
• [x] I am using the latest version of the Claude desktop app

What's Wrong?

In the Claude desktop app (Windows), Read Aloud always speaks Portuguese with a Brazilian accent, even though Settings > General > Voice > Language is set to "Portuguese (Portugal)" and the panel shows Style "Clara", Speed "Fast".

The setting is shown correctly in the UI, but it is not applied to Read Aloud.

Two things I could observe from the app's own analytics events (Local Storage, voice_settings_panel_changed) that may help pinpoint it:

1. Changing the display language resets the voice to pt-BR. Selecting "Português" in the profile menu > Language (which is Brazilian Portuguese, the only Portuguese UI locale) fired setting: "voice", from_value: "pt-pt-clara", to_value: "pt-BR-clara", triggered_by_language_change: true. Note the previously stored id was lower-case pt-pt-clara, while the new ids are pt-PT-clara / pt-BR-clara, so the old value may not have matched anything.
2. The voice keeps being re-derived as pt-BR. After I set Voice > Language back to "Portuguese (Portugal)" (setting: "language", from_value: "pt", to_value: "pt-PT", then setting: "voice", from_value: "pt-BR-clara", to_value: "pt-PT-clara"), every later change in the panel (e.g. speed 1 -> 1.2) again logged from_value: "pt-BR-clara", to_value: "pt-PT-clara". So the effective value appears to fall back to pt-BR-clara each time.
3. Read Aloud does not use the selected voice at all. Every claudeai.read_aloud.started event carries voice_id: "buttery", not pt-PT-clara.

This is server-side TTS, not a Windows voice: the only Portuguese voice installed on this machine is Microsoft Helia (pt-PT), there is no pt-BR system voice, and the audio does not match any local voice.

Setting the display language back to English, re-selecting "Portuguese (Portugal)" in Voice settings and fully quitting/restarting the app does not fix it.

What Should Happen?

With Voice > Language = "Portuguese (Portugal)", Read Aloud (and voice mode) should use a European Portuguese voice/pronunciation model. Changing the UI display language should not silently reset the voice language, and the panel should not show a value that differs from the one actually used.

Error Messages/Logs

# app analytics events (Local Storage), account ids removed
17:13:42  setting=language  from=en-US        to=pt           (profile menu > Language)
17:13:42  setting=voice     from=pt-pt-clara  to=pt-BR-clara  triggered_by_language_change=true
17:13:54  setting=language  from=pt           to=pt-PT        speech_language=pt-PT
17:13:54  setting=voice     from=pt-BR-clara  to=pt-PT-clara  triggered_by_language_change=true
17:14:00  setting=speed     from=1            to=1.2
17:14:00  setting=voice     from=pt-BR-clara  to=pt-PT-clara  triggered_by_language_change=true   <- still "from pt-BR"
17:14:07  setting=speed     from=1            to=1.2
17:14:07  setting=voice     from=pt-BR-clara  to=pt-PT-clara  triggered_by_language_change=true   <- still "from pt-BR"
17:14:18  claudeai.read_aloud.started  voice_id=buttery
17:17:21  claudeai.read_aloud.started  voice_id=buttery
17:22:38  claudeai.read_aloud.started  voice_id=buttery

Steps to Reproduce

1. Claude desktop app on Windows, account/UI language English.
2. Settings > General > Voice: set Language to Portuguese (Portugal), Style Clara, any speed. Close settings.
3. Ask Claude something in Portuguese and press Read Aloud on the reply.
4. The reply is read with a Brazilian Portuguese accent/pronunciation.
5. (Optional) Profile menu > Language > Português: the Voice language is silently reset to Brazilian; setting it back to Portuguese (Portugal) does not change what Read Aloud plays.
6. Fully quit the app from the tray icon and reopen: same result.

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Claude Code Version

Claude desktop app 2.9939.2 (Windows)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

• Windows 10 Pro 19045, system locale pt-PT.
• Installed Windows TTS voices: en-US (David, Zira, Mark), en-GB (Hazel, George, Susan), pt-PT (Helia). No pt-BR voice, so the Brazilian accent is not coming from the OS.
• Related: #85239 (Read Aloud applies wrong pronunciation model for German).