CardLanguagePreferenceIfAvailable

Localizes API error messages to the cardholder's preferred language when available, falling back to the device locale otherwise. If either locale is not supported by Stripe's localization infrastructure, error messages will fall back to English (en-US).

During a transaction, if the card provides a language preference and the connected reader supports extracting it, that language is used. Card language preference extraction is supported on smart readers (contact transactions, v2.43+) and Tap to Pay on Android. Mobile readers (Bluetooth/USB) always fall back to the device locale.

Use this option when you want error messages to automatically follow the device locale, or in customer-facing scenarios where the cardholder needs to understand the card decline error message.