Hi
Just for clarification - I dont installed the Welsh tts or created one.
I have IVONA English British and English Welsh voices installed.
They are both for the English TTS one with British accent and other is with Welsh one - like if you will have English Male and Female voices installed.
In the system settings the language is set to English (UK) one as per installed voices and the default one is set to British Amy voice.
In OsmAnd the voice sometimes is changing to Welsh one - but this is happening very rarely.
(e.g if you will have male and female voices installed with female one set up as default one and software will randomly switch to male voice without a reason - hope described correctly)
Regards,
Areg