FEATURE:       Explanation:
Vocal-auditory channel Communicator speaks; receiving individual hears.
Broadcast transmission;    
directional reception
Message goes out in all directions;
receiver can tell what direction message comes from.
(Sign language uses line-of-sight transmission instead.)
Rapid fading Message is transitory and does not persist.
Interchangeability Transmitters can become receivers, and vice versa;
we can each repeat any message.
Total feedback We hear all that we say.
Specialization We communicate just for the purpose of communicating
(not incidentally to some other primary function).
Direct energy consequences are unimportant.
Semanticity Symbols used (phonemes, morphemes) have particular meanings.    
Arbitrariness Symbols are arbitrary: the work "loud" can be spoken softly;
"whale" is a smaller word than "microorganism";
"dog", "perro", "chien", "hund", "canis" all mean the same.
Discreteness Symbols are made by combining smaller symbols
that differ discontinuously (e.g., "bin", "pin").        
Duality of patterning The smaller symbols ("p", "t") have no meaning of their own,
and can be combined in various ways ("pit", "tip").
Hockett originally thought that the remaining features were exclusively human.
Displacement You can talk about something not immediately present
(at a distance, or in the past).
Prevarication We can say things that are false or hypothetical.
Productivity Novel utterances can be made and understood.
Traditional transmission
Languages are socially learned (not genetic),
  and are passed down through generations.
Learnability We can learn new languages (easier in childhood).
Reflexiveness We can use language to talk about language
(e.g., "noun", "adjective", "sentence")

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