blather vs blither

blather

verb
  • To say (something foolish or nonsensical); to say (something) in a foolish or overly verbose way. 

  • To talk rapidly without making much sense. 

noun
  • Nonsensical or foolish talk. 

blither

verb
  • to talk foolishly; to blather 

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