yea vs yus

yea

adv
  • Thus, so (now often accompanied by a hand gesture by way of measurement). 

noun
  • An affirmative vote, usually but not always spoken 

intj
  • Yeah, right, yes. 

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