/**
 * Constants used for BCP-47 language tag validation
 */
/**
 * Regular expressions for validating subtags
 */
export declare const SUBTAG_REGEX: {
    LANGUAGE: RegExp;
    LANGUAGE_4: RegExp;
    LANGUAGE_5_TO_8: RegExp;
    EXTLANG: RegExp;
    SCRIPT: RegExp;
    REGION: RegExp;
    VARIANT: RegExp;
    SINGLETON: RegExp;
    EXTENSION: RegExp;
    PRIVATEUSE: RegExp;
};
/**
 * Regular expression for the entire language tag, based on the ABNF grammar in RFC 5646
 * This is a simplified version that validates the general structure but not all specific rules
 */
export declare const LANGUAGE_TAG_REGEX: RegExp;
/**
 * The grandfathered irregular tags as defined in RFC 5646
 */
export declare const IRREGULAR_GRANDFATHERED_TAGS: string[];
/**
 * The grandfathered regular tags as defined in RFC 5646
 */
export declare const REGULAR_GRANDFATHERED_TAGS: string[];
/**
 * All grandfathered tags
 */
export declare const GRANDFATHERED_TAGS: string[];