sie vs sough

sie

verb
  • To sink; fall; drop. 

  • To strain, as milk; filter. 

  • To drop, as water; trickle. 

  • To fall, as in a swoon; faint. 

  • To sift. 

noun
  • A drop. 

pron
  • Gender-neutral subject pronoun, grammatically equivalent to the gendered pronouns he and she 

sough

verb
  • To drain. 

  • To make a soft rustling or murmuring sound. 

noun
  • A gentle breeze; a waft; a breath. 

  • A murmuring sound; rushing, rustling, or whistling sound. 

  • A (deep) sigh. 

  • A small drain; an adit. 

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