HomoFast-eSpeak-Persian/docs/phoneme_model.md

Phoneme Model

• Manner of Articulation
  • Air Flow
  • Initiator
  • Target
  • Manner
• References

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Evan Kirshenbaum’s feature set used in his ASCII transcription of the International Phonetic Alphabet (IPA)^{[1], [2]} describes the phonemes in a way consistent with how the phonemes are organised in the IPA code chart. That is the approach used in the Phonemes document to describe the phonemes in a phoneme definition file.

Those phoneme features often represent the action of more than one articulatory mechanism used to produce speech, or affect the same area. Internally, espeak-ng makes use of the articulatory model, not the IPA descriptions. This document describes how the feature-based IPA model is mapped to the articulatory model.

People working on adding new voices or languages do not need to read this document, but should instead read the Phonemes document. This is intended for people working on the espeak-ng codebase, or people interested in how espeak-ng works internally.

NOTE: This model is in the process of being implemented. As such, the current implementation does not reflect this document.

Manner of Articulation

The manner of articulation is described in terms of several distinct feature types. The possible manners of articulation are:

Manner of Articulation	Feature	Phoneme Model
nasal	nas	pmc egs nsl occ
plosive (stop)	stp	pmc egs orl occ
affricate	afr	pmc egs orl occ frr
fricative	frc	pmc egs orl frv
tap/flap	flp	pmc egs orl fla
trill	trl	pmc egs orl tri
approximant	apr	pmc egs orl app
click	clk	vlc igs orl
ejective	ejc	vlc igs orl occ
implosive	imp	gtc igs
vowel	vwl	pmc egs orl vow

For imp consonants, they use the features of the base phoneme except for the pmc and egs features. Thus, a nas imp is a gtc igs nsl occ.

The vwl phonemes are described using vowel height and backness features, while consonants (the other manners of articulation) are described using place of articulation features.

Additionally, the manner of articulation can be refined using the following features:

Feature	Name	Description
lat	lateral	The air flow is directed along the sides of the tongue.
sib	sibilant	The air flow is directed through the teeth with the tongue.

Air Flow

Feature	Name	Description
egs	egressive	The air flow is moving outwards from the initiator to the target.
igs	ingressive	The air flow is moving inwards from the target to the initiator.

Initiator

Feature	Name	Description
pmc	pulmonic	The diaphragm and lungs are used to generate the airstream.
gtc	glottalic	The glottis is used to generate the airstream.
vlc	velaric	The velum is closed and the tongue is used to generate the airstream.
pcv	percussive	There is no airstream used to produce this sound.

Target

Feature	Name	Description
nsl	nasal	The air flows through the nose.
orl	oral	The air flows through the mouth.

Manner

Feature	Name	Description
occ	occlusive	The air flow is blocked within the vocal tract.
frv	fricative	The air flow is constricted, causing turbulence.
fla	flap	A single tap of the tongue against the secondary articulator.
tri	trill	A rapid vibration of the primary articulator against the secondary articulator.
app	approximant	The vocal tract is narrowed at the place of articulation without being turbulant.
vow	vowel	The phoneme is articulated as a vowel instead of a consonant.

References

1. Kirshenbaum, Evan, Representing IPA phonetics in ASCII (HTML). 1993.

2. Kirshenbaum, Evan, Representing IPA phonetics in ASCII (PDF). 2001.

3. International Phonetic Association, The International Phonetic Alphabet and the IPA Chart. 2015. Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA).

4. Wikipedia. International Phonetic Alphabet. 2017. Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA).

5. Wikipedia. Extensions to the International Phonetic Alphabet. 2017, Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA).