The Design Features of Language was a phrase coined in the 1960s by the American linguist Charles Hockett. Hockett believed that there existed 16 features of human language that distinguished human communication from that of animals. Charles Hockett also articulated that even the most basic human languages contained all 16 features. While the list initially contained 13 features, in a subsequent article Hockett expanded his list with three more features, for a total of sixteen:

1. Vocal auditory channels – Spoken language is produced in the vocal tract and transmitted/heard as sound, whereas sign language is produced with the hands and transmitted by light.
2. Broadcast transmission and directional reception – The audible sound of language is heard in all directions but listeners will interpret it as coming from one specific direction.
3. Rapid fading – The sound made by speech diminishes quickly after being released.
4. Interchangeability
   Interchangeability
   Interchangeability can refer to:*Interchangeability : A condition in which exist two or more items with characteristics making them equivalent in performance and durability, making them fully exchangeable....
   
    – The speaker has the ability to receive and also send the same message.
5. Total feedback – Individuals are able to hear and internalize a message they have sent.
6. Semanticity – Speech sounds can be linked to specific meanings.
7. Arbitrariness – There is no direct connection between the signal and its meaning.
8. Discreteness
   Discrete mathematics
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    – Each unit of communication can be separated and unmistakable.
9. Specialization – Speech is produced for communication, not chiefly for some other function, such as echolocation
   Human echolocation
   Human echolocation is the ability of humans to detect objects in their environment by sensing echoes from those objects. By actively creating sounds – for example, by tapping their canes, lightly stomping their foot or making clicking noises with their mouths – people trained to orientate with...
   
   .
10. Displacement
    Displacement (linguistics)
    In linguistics, displacement is the capability of human language to communicate about things that are not immediately present.In 1960, Charles F. Hockett proposed displacement as one of 13 "design-features" that distinguish human language from animal language:...
    
     – The ability to talk about things that are not physically present.
11. Productivity
    Productivity (linguistics)
    In linguistics, productivity is the degree to which native speakers use a particular grammatical process, especially in word formation. Since use to produce novel structures is the clearest proof of usage of a grammatical process, the evidence most often appealed to as establishing productivity is...
    
     – The ability to create new messages by combining already-existing signs.
12. Traditional transmission
    Traditional Transmission
    Traditional transmission is a design feature of language that the anthropologist Charles F. Hockett developed to distinguish the features of human language from those of animal communication. He discovered thirteen features that all human languages have. Animals might communicate with some of the...
    
     – The learning of language occurs in social groups.
13. Duality of patterning – Meaningful signs (words) are made of—and distinguished from one another by—meaningless parts (sounds, letters)
14. Prevarication – The ability to make false statements (to lie).
15. Reflexiveness – Language can be used to refer to (i.e., describe) itself.
16. Learnability
    Learnability
    -Software testing:In software testing learnability, according to ISO/IEC 9126, is the capability of a software product to enable the user to learn how to use it...
    
     – Speakers of one language can learn to speak another.

It was Hockett's belief that the first nine features were characteristics of communication held by all primates. Hockett determined that the last seven features are what distinguishes human language from all others.