ja vs yus

ja

adv
  • yes 

noun
  • Synonym of Korean foot: a traditional unit of length equivalent to about 30.3 cm. 

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 ja and yus occurred in a corpus of books? (source: Google Ngram Viewer )