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 are closed little yus (Ꙙ ꙙ), iotated closed little yus (Ꙝ ꙝ) and blended yus (Ꙛ ꙛ).

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”). This is also suggested by the appearance of each as a 'stacked' digraph of 'Am' and 'Om' respectively.

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