The Nature of Words in Human Protolanguages

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The Nature of Words in Human Protolanguages

• Mike Dowman
• November 16, 2006

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Protolanguage

• At some time in the past humans didnt have
  language.
• Was the emergence of human language gradual or
  sudden?
• What did the first first human languages look
  like?

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Starting Small

• First humans could only articulate and/or
  perceive a limited number of distinct words
• No phonology
• Little or no syntax (one word utterances)
• They only tried to convey limited number of
  simple meanings

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Bickerton (1990, 1996)

• Words in first languages were like modern words
• Labeled preexisting concepts and entities
• Words used in short strings
• No fixed word order
• Words can be omitted

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Modern Day Examples of Protlanguage

• Children under two
• Speakers of pidgins
• Adults deprived of language in childhood
• Trained apes
• Nim eat Nim eat
• Tickle me Nim play
• Me banana you banana me you give
• Banana me me me eat

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Wray (1998)

• The First Words in Protolanguages were
  Holophrastic
• Each word conveyed a whole complex meaning (e.g.
  Give me the meat)
• Chimpanzee vocal noises and gestures are holistic
• Inform about location of food, threaten, get
  another chimpanzee to do something

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The Iterated Learning Model(a.k.a.
Expression-Induction Model)

• Language is passed from generation to generation
  through a limited number of spoken examples
• Each new generation must try to infer the
  underlying system

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Nature of Utterances

• Each utterance consisted of only a single word
• Agents could use only a small number of words
  (limited communicative capacity)
• Available words fixed throughout each simulation

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Meaning Representations

• Small number of semantic primitives (limited
  conceptual capacity)
• Each utterance would try to express a complex
  meaning represented by a group of three different
  primitives
• hunt, pig, forest means Hunt pigs in the forest
• dog, pig, sleep means Dogs and pigs are sleeping

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Agents Choice of Words

• Agents use the word whose past uses have been
  most similar to the current meaning
• If current meaning is eat, house, pig
• Previously heard used to express
• eat, house, dog
• hunt, forest, pig Match 4/9
• hunt, forest, pig

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Agents Choice of Words

• If degree of match is one, agent will always use
  that word
• Otherwise will use any available unused word (and
  the word-meaning pair remembered)
• Otherwise pick highest degree of match (choosing
  at random in the event of a tie)

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Simulations

• Each meaning contained 3 elements from a set of
  10 (so 120 distinct complex meanings)
• Each agent produced 1000 utterances for the agent
  in the next generation (each expressing a
  randomly chosen meaning)
• Simulations were run for ten generations
• The number of available words was varied

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Emergence of Modern Types of Word

• In the first simulation the agents could only use
  10 distinct words
• All the agents made use of all 10 available words
• Most words were used only when one particular
  semantic element was present
• Their meanings appear to correspond to those
  elements

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Example Modern Type Words

• The words are like modern nouns or verbs

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Emergence of Holophrastic Words

• In the next simulation the agents could use 150
  distinct words
• All agents used 120 of these words
• Each word expresses a single complex meaning
• These words are all holophrastic

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Example Holophrastic Words
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Emergence of Intermediate Types of Language

• What happens when the number of available words
  is in between the number of semantic elements and
  the number of complex meanings?
• Do we get a mixture of modern type and
  holophrastic words?
• A new simulation with 50 available words tested
  this
• All agents used all the available words

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• Language contains words with varying degrees of
  holophrasticity
• Its intermediate between a protolanguage with
  modern words and a holophrastic one

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Varying Degrees of Holophrasticity

• The frequency of each type of word depended on
  the number of distinct words available
• With 50 words there were
• 10 holophrastic words, 35 words containing two
  fixed semantic elements, 4 words containing one
  fixed element, and 1word containing no fixed
  elements at all
• With a smaller number of distinct words, the
  languages become less holophrastic
• With more available words they became more
  holophrastic

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Fewer Words than Semantic Elements

• What if the agents could not even produce one
  distinct word for each semantic element?
• (Or alternatively what if they knew so many
  semantic elements they could use more than there
  were words?)
• A new simulation was conducted with only 5
  distinct words available

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Emergent Words

• Three words had one fixed semantic element
• One word used any three of the other seven
  semantic elements
• The final word contains at least two of the
  elements eat, gather and pig
• This is a new type of word, and is partly
  holophrastic

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Co-evolution of Agents and Protolanguages

• What happens as agents communicative and
  conceptual capacities evolve phylogenetically?
• We would expect the agents protolanguages to
  rapidly adapt to the agents new capacities
• How will the degree of holophrasticity change
  over time?

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Increasing Communicative Capacity

• The first agents could use only a single word
• After every 10 generations the number of words
  they could use was increased by 1
• Number of semantic elements fixed at 10
• 1300 generations simulated

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Increasing Conceptual Complexity

• In this simulation there were always 120 words
  available
• Initially there were 10 semantic elements
• After every 10 generations the number of
  available semantic elements was increased by 1
• This simulation was also run over 1300
  generations (so there were 447,580 different
  complex meanings at the end of the simulation)

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Transitions between Modern and Holophrastic Words

• The first simulation showed a progression from
  modern words to holophrasis
• The second from holophrasis to modern words
• So depending on the relative rates of monotonic
  evolution of communicative and conceptual
  capacity we could see multiple swings between
  each type of protolanguage

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E-Language and I-Language

• If we look at agents internal linguistic
  representations (I-Language) we only see an
  unanalyzed list of the past uses of a word
• However, if we could only observe the agents
  speech (E-Language) and the meanings they tried
  to express we would (in some cases) be able to
  identify the words with specific semantic
  elements
• So a categorization ability is not necessary for
  a language with categorical words to emerge

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Key Points

• Modern type words or Holophrases are not the only
  possibilities for Protolanguages.
• If agents try to express a limited number of
  meanings (relative to their communicative
  abilities) holophrasis will results.
• With more meanings or fewer words forms, words
  become less holophrastic and more like modern
  words.
• The modern type word vs. holophrasis debate is
  not as clear cut as it might at first seem