-ee vs -ity

-ee

suffix
  • Irregularly added to nouns to mean a person somehow associated with the object denoted by the noun. 

  • Used to form words meaning a person who has undergone a particular medical procedure. 

  • Used to form diminutives. 

  • Less commonly added to intransitive verbs to form words meaning a person or thing that is the subject of that verb (that is, who or that does an action). 

  • Used in mimicking English as stereotypically spoken by the Chinese. 

  • Used to form words meaning a person who is the other party to a contract or other transaction involving a person described by the corresponding word ending in -or. 

  • Added to transitive verbs to form words meaning a person or thing that is the object of that verb (i.e., to whom or to which an action is done). 

-ity

suffix
  • Used to form a noun from an adjective; especially, to form the noun referring to the state, property, or quality of conforming to the adjective's description. 

  • Used to form other nouns, especially abstract nouns. 

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