Yus

Little yus (Ѧ, ѧ; italics: Ѧ, ѧ) and big yus (Ѫ, ѫ; italics: Ѫ, ѫ), or jus, are letters of the Cyrillic script representing two Common Slavonic nasal vowels in the early Cyrillic and Glagolitic alphabets. Each can occur in iotated form (Ѩ ѩ, Ѭ ѭ), formed as ligatures with the decimal i (І). Other yus letters like the closed little yus (Ꙙ ꙙ), iotated closed little yus (Ꙝ ꙝ) and blended yus (Ꙛ ꙛ), are also used.

Phonetically, little yus represents a nasalized front vowel, possibly [ɛ̃] (like the French ‘in’ in “cinq” or Polish 'ę' in “kęs”), while big yus represents a nasalized back vowel, such as IPA [ɔ̃] (like the French ‘on’ in “bombon” or Polish 'ą' in “kąt”).

The names of the letters do not imply capitalization, as both little and big yus exist in majuscule and minuscule variants.