You can speak whatever language you want on the air so long as you identify every ten minutes and at the end of your transmission. The ITU regulations for radio call signs cover their format however and use the Latin alphabet. Call books are also public so anyone can look up the stations and know who you are.

Speaking in shorthand to be clear and concise over the radio is fine. Even using terms of art or abbreviations is likely fine. If you're explicitly coding your communication to obfuscate its meaning you're definitely going to run afoul on the ban of encryption.

Part of the reason for no encryption on ham bands is there's precious little bandwidth available and unintelligible signals (intentionally obfuscated) are tantamount to interference. As a listener I can't reasonably tell if an encrypted signal is noise or a genuine call. I also can't reasonably receive a call sign so I can't know who is transmitting.