tongue-tied vs vocative

tongue-tied

adj
  • Reluctant to speak up; reserved, reticent. 

  • Having tongue-tie or ankyloglossia (“a congenital oral anomaly in which the lingual frenulum (a membrane connecting the underside of the tongue to the floor of the mouth) is unusually short and thick, decreasing mobility of the tongue and affecting eating, speech, etc.”). 

  • Physically unable to speak; dumb, mute. 

  • Prevented from or unable to express oneself clearly or fluently, or freely; at a loss for words, speechless. 

vocative

adj
  • Of or pertaining to calling; used in calling or vocation. 

  • Used in address; appellative (said of that case or form of the noun, pronoun, or adjective, in which a person or thing is addressed). For example "Domine, O Lord" 

noun
  • The vocative case 

  • A word in the vocative case 

  • Something said to (or as though to) a particular person or thing; an entreaty, an invocation. 

How often have the words tongue-tied and vocative occurred in a corpus of books? (source: Google Ngram Viewer )