declare vs mutter

declare

verb
  • To assert or announce formally, officially, explicitly, or emphatically. 

  • To make outstanding debts, e.g. taxes, payable. 

  • To show one's cards in order to score. 

  • To explicitly establish the existence of (a variable, function, etc.) without necessarily describing its content. 

  • For a constituency in an election to officially announce the result 

  • For the captain of the batting side to announce the innings complete even though all batsmen have not been dismissed. 

  • To inform government customs or taxation officials of goods one is importing or of income, expenses, or other circumstances affecting one's taxes. 

mutter

verb
  • To speak softly and incoherently, or with imperfect articulations. 

  • To make a sound with a low, rumbling noise. 

  • To utter words, especially complaints or angry expressions, indistinctly or with a low voice and lips partly closed; to say under one's breath. 

noun
  • A repressed or obscure utterance; an instance of muttering. 

  • Peas. 

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