1. 5-Text To Speech (TTS) Speech Synthesis
Speech Synthesis Concept
Phone Units
Phone Sequence To Speech
Speech Naturalness
Concatenative Approaches
Rule-Based Approaches

2. Speech Synthesis Concept
Text
Speech
Text
Text to
Phone Sequence
Phone Sequence
to Speech
Speech
Natural Language
Processing (NLP)
Speech Processing

3. Phone Units Paragraph ( ) Sentence ( )
Word (Depends on the language. Usually more than 100,000)
Syllable
Diphone & Triphone
Phoneme (Between 10 , 100)

4. Phone Units (Cont’d)
Diphone : We model Transitions between two phonemes p1 p2 p3 p4 p5
Diphone
Phoneme

5. Phone Units (Cont’d)
In farsi we have 30 Phoneme. so we have 30*30 Diphone Theoretically.
Practically the only Diphone that we don’t have in farsi is /zho/
we have Triphone Theoretically. But practically we have about Triphone in farsi.

6. Phone Units (Cont’d) Syllable = Onset (Consonant) + Rhyme
Syllable is a set of phonemes that exactly contains one vowel
Syllables in Farsi : CV , CVC , CVCC
We have about 4000 Syllables in farsi
Syllables in English :V, CV , CVC ,CCVC, CCVCC, CCCVC, CCCVCC, . . .
Number of Syllables in English is very much

7. Phone Sequence To Speech
Concatenative Approaches : Trade-Off between Naturality And Memory usage and variety of desired functions
Rule-Based Approaches : The most important Rule-Based approach is Klatt method

8. Phone Sequence To Speech (Cont’d)
to primitive
utterance
primitive
utterance
to Natural
Speech
Text to
Phone
Sequence
Speech
Text
NLP
Speech Processing

9. Speech Naturalness
Obviation of undesirable noise and distortion and dissociation from speech
Prosody generation
Speech energy
Duration
pitch
Intonation
Stress

10. Speech Naturalness (Cont’d)
Intonation and Stress are very effective in speech naturalness
Intonation : Variation of Pitch frequency along speaking
Stress : Increasing the pitch frequency in a specific time

11. Concatenative Approaches
In this approaches we store units of natural speech for reconstruction of desired speech
We could select the appropriate phone unit for speech synthesis
we can store compressed parameters instead of main waveform

12. Concatenative Approaches (Cont’d)
Benefits of storing compressed parameters instead of main waveform
Less memory use
General state instead of a specific stored utterance
Generating prosody easily

13. Concatenative Approaches (Cont’d)
Phone Unit
Type of Storing
Paragraph
Sentence
Word
Syllable
Diphone
Phoneme
Main Waveform
Coded/Main Waveform
Coded Waveform

14. Concatenative Approaches (Cont’d)
Pitch Synchronous Overlap-Add-Method (PSOLA) is a famous method in phoneme transmit smoothing
Overlap-Add-Method is a standard DSP method
PSOLA is a base action for Voice Conversion.
In this method in analysis stage we select frames that are synchronous by pitch markers.

15. Rule-Based Approach Stages
Determine the speech model and model parameters
Determine type of phone units
Determine some parameter amount for each phone unit
Substitute sequence of phone units by its equivalent parameter sequence
Put parameter sequence in speech model

16. KLATT 80 Model

17. KLATT 88 Model

18. THE KLSYN88 CASCADE PARALLEL FORMANT SYNTHESIZER
FNP FNZ FTP FTZ F1 B1
BNP BNZ BTP BTZ DF1 DB F2 B F3 B F4 B F5 B5
GLOTTAL SOUND SOURCES
NASAL
POLE ZERO PAIR
TRACHEAL POLE ZERO PAIR
FIRST FORMANT RESONATOR
SECOND FORMANT RESONATOR
THIRTH FORMANT RESONATOR
FOURTH FORMANT RESONATOR
FIFTH FORMANT RESONATOR
FILTERED IMPULSE TRAIN TL
CASCADE VOCAL TRACT MODEL LARYNGEAL SOUND SOURCES
F0 AV OO FL DI
SPECTRAL TILT LOW-PAS RESONANTOR
KL GLOTT 88 model (default) SS CP +
NASAL FORMANT RESONATOR AH
ANV
ASPIRATION NOISE GENERATOR SO
MODIFIED LF
MODEL
FIRST FORMANT RESONATOR
A1V
SECOND FORMANT RESONATOR
B2F + -
A2F
FIRST DIFFERENCE PREEMPHASIS
SECOND FORMANT RESONATOR
A2V +
THIRD FORMANT RESONATOR
B3F
A3F
THIRTH FORMANT RESONATOR AF
A3V
FRICATION NOISE GENERATOR
FOURTH FORMANT RESONATOR
B4F
A4F
FOURTH FORMANT RESONATOR
A4V
FIFTH FORMANT RESONATOR
B5F + -
A5F
TRACHEAL FORMANT RESONATOR
ATV
B6F F6
SIXTH FORMANT RESONATOR
A6F AB
PARALLEL VOCAL TRACT MODEL LYRYNGEAL
SOUND SOURCES (NORMALLY NOT USED)
BYPASS PATH
PARALLEL VOCAL TRACT MODEL FRICATION SOUND SOURCES

19. Three Voicing Source Model In KLATT 88
The old KLSYN impulsive source
The KLGLOTT88 model
The modified LF model