yo vs yus

yo

noun
  • The letter Ё, ё. 

pron
  • third-person singular, familiar 

intj
  • An expression of surprise or excitement. 

  • An interjection similar to hey. 

  • A greeting similar to hi. 

  • Present! Here! 

  • Emphatic conclusion to a statement. 

yus

noun
  • Either of two letters, little yus (Ѧ) and big yus (Ѫ), representing nasal vowel sounds in the Cyrillic alphabet. The only major Slavic language retaining these sounds is Polish, which is written in the Latin alphabet. 

How often have the words yo and yus occurred in a corpus of books? (source: Google Ngram Viewer )