/**
 * Sets the language for this user. By default, the user's language is detected automatically
 * from the device. If you call this method, Braze will ignore the detected language and use
 * the language you have provided instead.
 *
 * @param language - An [ISO 639-1 Language Code](https://www.w3schools.com/tags/ref_language_codes.asp).
 *   Accepts an explicit null value to null out attribute.
 *
 * @returns Resolves to a boolean that indicates whether the update was successfully enqueued. Resolves to undefined
 *   if the SDK is not initialized.
 */
export declare function setUserLanguage(language: string | null): Promise<boolean | undefined>;