Both, iOS and Android allow to inform VoiceOver/TalkBack about the language the a11y properties like Accessible.name and Accessible.description use:

iOS

• https://developer.apple.com/documentation/objectivec/nsobject-swift.class/accessibilitylanguage?language=objc

Android

• https://developer.android.com/reference/android/text/style/LocaleSpan
• https://developer.android.com/reference/android/text/SpannableString#setSpan(java.lang.Object,%20int,%20int,%20int)

This allows users to set a different app language than their OS language and still have the app's text read in the correct language package. E.g. if the app is missing translations for their locale but provides english texts the user understands.

Currently, the language used in-app is not communicated to the Screen Reader, resulting in voice output that has a confusing accent if the language settings between OS and app mismatch.

See the attached MWE to reproduce the issue.

This issue is somewhat related to QTBUG-140337 as there is no currently no simple or streamlined way to retrieve the app's language.