First Message language preference

I have a question

In our bot implementation using Web Chat, we have a default welcome card that is triggered via the ConversationUpdate activity. However, even when we pass the user's locale to Web Chat during initialization, this first welcome card always shows in English.

Only after the user sends a message or performs an action that includes the locale, the bot starts responding in the user's preferred language. The issue is that the locale is not being set early enough, so the initial welcome card does not respect the language preference.

Requirement:

We need the bot to send the first welcome card in the correct locale, based on the user's language preference — without requiring any user activity first. The locale should be correctly applied right from the start of the conversation.

Could someone guide me here on how can I get over this issue?

Start by tracing Web Chat initialization and the ConversationUpdate activity, focusing on when the user's locale becomes available. Verify that the initial welcome card uses the preferred locale before any user message or action, and confirm the behavior with a localized first response.