lo vs wallah

lo

abbrev
  • hello ('lo; see hallo) 

wallah

adv
  • by God (Allah); may God be my witness used in making a solemn oath 

noun
  • A servant or other person responsible for something, often specified before it, for example kitchen wallah. 

  • A guy or bloke. 

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