How to add new languages (alphabets)

There are 2 alphabets (latin-cyrl) in Uzbek language. When add uz_Uz, only showing latin characters. How to add second (another) alphabet? If add uz-Cyrl (uz_Cyrl, uz_Cyrl_UZ etc.), reject by system.

O’zbekcha A B D E F G H G’ O’
?збекча А Б Д Е Ф Г ? ? ?

uz-Cyrl
uz-Latn