Week 15. Speech Engineering Overview

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Week 15. Speech EngineeringOverview

• Linguistic background
• Phonetics
• Phonology
• Engineering background
• Acoustics
• Mathematics
• Computer science

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Subfields of application

• Speech Recognition
• Let machines hear
• Simulating human speech perception
• Speech Synthesis
• Let machines say
• Simulating human speech production
• Automatic Translation
• Ultimate goal
• Needs other sub-areas

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Speech synthesis- short history

• Before 1970s
• Analogue vocal tract model
• After 1970s
• PC hardwares
• After 1990s
• PC softwares
• Text-to-speech (TTS) systems

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Speech synthesis- basic processes

• Recording of human voice
• Cutting into units
• Coping and pasting of various units
• Units
• phones, phonemes, syllables, words

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Speech synthesis- problems

• Transitions and coarticulation
• Solution Introducing new units
• diphones
• triphones
• demisyllables
• Prosody
• Solution
• duration modelling
• pitch modelling

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Text-to-speech conversion processes

• Data input
• Linguistic Process
• Morphological Analysis
• Syntactic Analysis
• Letter-to-Phoneme conversion
• Prosodic control
• Speech generation

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Speech recognition- application

• Voice dictation
• Automobile maneuver control
• Operation of home appliances
• Speaker identification
• Speaker verification

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Speech recognition- short history

• 1930s getting interested
• 1940s spectrograph invented
• 1950s, 60s isolated word recognition
• 1970s interested in connected speech
• 1980s statistical approach

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Speech recognition-quality control

• Word sequence
• Isolated words / Connected speech
• Naturality
• Read speech / Spontaneous speech
• Spontaneous dialogue
• Speaker
• Speaker dependent/independent system
• Language
• Language dependent/independent system
• Vocabulary size
• Small / medium/ large size vocabulary
• Vocabulary independent system

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Speech recognition- units

• Trade-off
• Efficiency and performance
• Units
• Words
• Phone-like units
• Diphones
• Triphones

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Speech recognition- Teniques

• Knowledge-based approach
• Statistical approach