export interface Langtag {
    langtag: {
        language: {
            language?: string | null;
            extlang: string[];
        };
        script: string | null;
        region: string | null;
        variant: string[];
        extension: {
            singleton: string;
            extension: string[];
        }[];
        privateuse: string[];
    };
    privateuse: string[];
    grandfathered: {
        irregular?: string | null;
        regular?: string | null;
    };
}
export declare function parse(tag?: string): Langtag | null;