On the human-readable zone ("VIZ" in ICAO 9303) yes, see part 3 section 3.1 [1]. The MRZ however, not - it is limited to Latin alphanumeric only, see section 4.3. How to transliterate non-Latin characters is left to the discretion of the issuing government, and that has been a consistent source of annoyances for people who have identity cards issued by different governments (e.g. dual-nationals of Western European and Turkish, Arabic or Cyrillic-using Slavic countries).

[1] https://www.icao.int/publications/Documents/9303_p3_cons_en....