/**
 * ISO 639 language codes registry
 * This file contains data for validating language subtags against the official registry
 */
/**
 * Map of valid ISO 639-1/639-2/639-3 language codes
 * Key: language code, Value: language name
 */
export declare const ISO_639_LANGUAGES: Record<string, string>;
/**
 * Map of common incorrect language codes to their correct forms
 * Key: incorrect code, Value: correct code
 */
export declare const LANGUAGE_CODE_CORRECTIONS: Record<string, string>;
/**
 * Map of preferred values for language codes
 * According to BCP-47 canonicalization rules
 */
export declare const LANGUAGE_PREFERRED_VALUES: Record<string, string>;
/**
 * Extended language subtags (ISO 639-3 codes used as extlang)
 * These can appear as extlang subtags after a macrolanguage
 */
export declare const EXTENDED_LANGUAGE_SUBTAGS: string[];
/**
 * Map of extlang subtags to their preferred values
 */
export declare const EXTLANG_PREFERRED_VALUES: Record<string, string>;
/**
 * Checks if a language code is valid according to ISO 639
 *
 * @param code The language code to validate
 * @returns True if the code is valid, false otherwise
 */
export declare function isValidLanguageCode(code: string): boolean;
/**
 * Gets a suggestion for an invalid language code
 *
 * @param code The invalid language code
 * @returns A suggested correction or undefined if no suggestion is available
 */
export declare function getSuggestedLanguageCode(code: string): string | undefined;
/**
 * Checks if a language code has a preferred value in the registry
 *
 * @param code The language code to check
 * @returns True if the code has a preferred value, false otherwise
 */
export declare function hasPreferredLanguageValue(code: string): boolean;
/**
 * Gets the preferred value for a language code
 *
 * @param code The language code to get the preferred value for
 * @returns The preferred value or the original code if no preferred value exists
 */
export declare function getLanguagePreferredValue(code: string): string;
/**
 * Checks if a code is an extended language subtag
 *
 * @param code The code to check
 * @returns True if the code is an extended language subtag, false otherwise
 */
export declare function isExtendedLanguageSubtag(code: string): boolean;
/**
 * Gets the preferred value for an extlang subtag
 *
 * @param code The extlang code to get the preferred value for
 * @returns The preferred value or the original code if no preferred value exists
 */
export declare function getExtlangPreferredValue(code: string): string;