Class to convert a language to a 2-letter country code and vice versa

Language.php

<?php

class Language {

    /*
     * Dictionary of languages with 2-letter country codes (adapted ISO 639-1)
     * @var array
     */
    protected static $dictionary = [
        'Abkhaz' => 'AB',
        'Afar' => 'AA',
        'Afrikaans' => 'AF',
        'Akan' => 'AK',
        'Albanian' => 'SQ',
        'Amharic' => 'AM',
        'Arabic' => 'AR',
        'Aragonese' => 'AN',
        'Armenian' => 'HY',
        'Assamese' => 'AS',
        'Avaric' => 'AV',
        'Avestan' => 'AE',
        'Aymara' => 'AY',
        'Azerbaijani' => 'AZ',
        'Bambara' => 'BM',
        'Bashkir' => 'BA',
        'Basque' => 'EU',
        'Belarusian' => 'BE',
        'Bengali' => 'BN',
        'Bangla' => 'BN',
        'Bihari' => 'BH',
        'Bislama' => 'BI',
        'Bosnian' => 'BS',
        'Breton' => 'BR',
        'Bulgarian' => 'BG',
        'Burmese' => 'MY',
        'Catalan' => 'CA',
        'Chamorro' => 'CH',
        'Chechen' => 'CE',
        'Chichewa' => 'NY',
        'Chewa' => 'NY',
        'Nyanja' => 'NY',
        'Chinese' => 'ZH',
        'Chuvash' => 'CV',
        'Cornish' => 'KW',
        'Corsican' => 'CO',
        'Cree' => 'CR',
        'Croatian' => 'HR',
        'Czech' => 'CS',
        'Danish' => 'DA',
        'Divehi' => 'DV',
        'Dhivehi' => 'DV',
        'Maldivian' => 'DV',
        'Dutch' => 'NL',
        'Dzongkha' => 'DZ',
        'English' => 'EN',
        'Esperanto' => 'EO',
        'Estonian' => 'ET',
        'Ewe' => 'EE',
        'Faroese' => 'FO',
        'Fijian' => 'FJ',
        'Finnish' => 'FI',
        'French' => 'FR',
        'Fula' => 'FF',
        'Fulah' => 'FF',
        'Pulaar' => 'FF',
        'Pular' => 'FF',
        'Galician' => 'GL',
        'Georgian' => 'KA',
        'German' => 'DE',
        'Greek' => 'EL',
        'Guaraní' => 'GN',
        'Gujarati' => 'GU',
        'Haitian' => 'HT',
        'Haitian Creole' => 'HT',
        'Hausa' => 'HA',
        'Hebrew' => 'HE',
        'Herero' => 'HZ',
        'Hindi' => 'HI',
        'Hiri Motu' => 'HO',
        'Hungarian' => 'HU',
        'Interlingua' => 'IA',
        'Indonesian' => 'ID',
        'Interlingue' => 'IE',
        'Irish' => 'GA',
        'Igbo' => 'IG',
        'Inupiaq' => 'IK',
        'Ido' => 'IO',
        'Icelandic' => 'IS',
        'Italian' => 'IT',
        'Inuktitut' => 'IU',
        'Japanese' => 'JA',
        'Javanese' => 'JV',
        'Kalaallisut' => 'KL',
        'Greenlandic' => 'KL',
        'Kannada' => 'KN',
        'Kanuri' => 'KR',
        'Kashmiri' => 'KS',
        'Kazakh' => 'KK',
        'Khmer' => 'KM',
        'Kikuyu, Gikuyu' => 'KI',
        'Kinyarwanda' => 'RW',
        'Kyrgyz' => 'KY',
        'Komi' => 'KV',
        'Kongo' => 'KG',
        'Korean' => 'KO',
        'Kurdish' => 'KU',
        'Kwanyama' => 'KJ',
        'Kuanyama' => 'KJ',
        'Latin' => 'LA',
        'Luxembourgish' => 'LB',
        'Letzeburgesch' => 'LB',
        'Ganda' => 'LG',
        'Limburgish' => 'LI',
        'Limburgan' => 'LI',
        'Limburger' => 'LI',
        'Lingala' => 'LN',
        'Lao' => 'LO',
        'Lithuanian' => 'LT',
        'Luba-Katanga' => 'LU',
        'Latvian' => 'LV',
        'Manx' => 'GV',
        'Macedonian' => 'MK',
        'Malagasy' => 'MG',
        'Malay' => 'MS',
        'Malayalam' => 'ML',
        'Maltese' => 'MT',
        'Māori' => 'MI',
        'Marathi' => 'MR',
        'Marshallese' => 'MH',
        'Mongolian' => 'MN',
        'Nauru' => 'NA',
        'Navajo' => 'NV',
        'Navaho' => 'NV',
        'Northern Ndebele' => 'ND',
        'Nepali' => 'NE',
        'Ndonga' => 'NG',
        'Norwegian Bokmål' => 'NB',
        'Norwegian Nynorsk' => 'NN',
        'Norwegian' => 'NO',
        'Nuosu' => 'II',
        'Southern Ndebele' => 'NR',
        'Occitan' => 'OC',
        'Ojibwe' => 'OJ',
        'Ojibwa' => 'OJ',
        'Old Church Slavonic' => 'CU',
        'Church Slavonic' => 'CU',
        'Old Bulgarian' => 'CU',
        'Oromo' => 'OM',
        'Oriya' => 'OR',
        'Ossetian' => 'OS',
        'Ossetic' => 'OS',
        'Panjabi' => 'PA',
        'Punjabi' => 'PA',
        'Pāli' => 'PI',
        'Persian' => 'FA',
        'Farsi' => 'FA',
        'Polish' => 'PL',
        'Pashto' => 'PS',
        'Pushto' => 'PS',
        'Portuguese' => 'PT',
        'Quechua' => 'QU',
        'Romansh' => 'RM',
        'Kirundi' => 'RN',
        'Romanian' => 'RO',
        'Russian' => 'RU',
        'Sanskrit' => 'SA',
        'Sardinian' => 'SC',
        'Sindhi' => 'SD',
        'Northern Sami' => 'SE',
        'Samoan' => 'SM',
        'Sango' => 'SG',
        'Serbian' => 'SR',
        'Scottish Gaelic' => 'GD',
        'Gaelic' => 'GD',
        'Shona' => 'SN',
        'Sinhala' => 'SI',
        'Sinhalese' => 'SI',
        'Slovak' => 'SK',
        'Slovene' => 'SL',
        'Somali' => 'SO',
        'Southern Sotho' => 'ST',
        'Spanish' => 'ES',
        'Sundanese' => 'SU',
        'Swahili' => 'SW',
        'Swati' => 'SS',
        'Swedish' => 'SV',
        'Tamil' => 'TA',
        'Telugu' => 'TE',
        'Tajik' => 'TG',
        'Thai' => 'TH',
        'Tigrinya' => 'TI',
        'Tibetan Standard' => 'BO',
        'Tibetan' => 'BO',
        'Central' => 'BO',
        'Turkmen' => 'TK',
        'Tagalog' => 'TL',
        'Tswana' => 'TN',
        'Tonga' => 'TO',
        'Turkish' => 'TR',
        'Tsonga' => 'TS',
        'Tatar' => 'TT',
        'Twi' => 'TW',
        'Tahitian' => 'TY',
        'Uyghur' => 'UG',
        'Ukrainian' => 'UK',
        'Urdu' => 'UR',
        'Uzbek' => 'UZ',
        'Venda' => 'VE',
        'Vietnamese' => 'VI',
        'Volapük' => 'VO',
        'Walloon' => 'WA',
        'Welsh' => 'CY',
        'Wolof' => 'WO',
        'Western Frisian' => 'FY',
        'Xhosa' => 'XH',
        'Yiddish' => 'YI',
        'Yoruba' => 'YO',
        'Zhuang' => 'ZA',
        'Chuang' => 'ZA',
        'Zulu' => 'ZU',
    ];

    /*
     * Get the 2-letter country code of a language
     *
     * @param string $language The language
     * @return string|null
     */
    public static function getCountryCode($language) {
        $language = ucwords(strtolower($language));

        foreach (self::$dictionary as $key => $value) {
            if ($key === $language) {
                return $value;
            }
        }

        return null;
    }

    /*
     * Get the language spoken in a country
     *
     * @param string $countryCode The 2-letter code of the country
     * @return string|null
     */
    public static function getLanguage($countryCode) {
        $countryCode = strtoupper($countryCode);

        foreach (self::$dictionary as $key => $value) {
            if ($value === $countryCode) {
                return $key;
            }
        }

        return null;
    }
}