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| Speech Recognition: language |
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| model |
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| | mapping
sound waves to a sequence of words |
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| | Its
hard to wreck a nice beach. |
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| | Probabilistic
Context-Free Grammars (PCFGs) |
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| | P(w1
w2
wN) = P(w1) * P(w2|w1) *
* P(wN|w1
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| w(N-1)) |
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| | CPTs
too large: |
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| | unigrams:
Approximate as P(w1) * P(w2) *
* P(wN) |
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| | bigrams:
Approximate as P(w1) * P(w2|w1) *
* P(wN|w(N-1)) |
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| | trigrams:Approximate
as P(w1) * P(w2|w1) * P(w3|w1,w2)
* |
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| P(wN|w(N-1),w(N-2)) |
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