# Phoneme Features and the International Phonetic Alphabet

- Phoneme Transcription Schemes
- Consonants
  - Other Symbols
  - Gemination
  - Manner of Articulation
  - Place of Articulation
  - Voice
- Vowels
  - Other Symbols
  - Rounding
  - Height
  - Backness
- Diacritics
  - Articulation
  - Air Flow
  - Phonation
  - Rounding and Labialization
  - Syllabicity
  - Consonant Release
  - Co-articulation
  - Tongue Root
  - Fortis and Lenis
- Suprasegmentals
  - Stress
  - Length
  - Rhythm
  - Tones
  - Intonation
- References

Evan Kirshenbaum created an ASCII transcription of the International Phonetic Alphabet (IPA)[1], [2]. As well as using ASCII characters for specific IPA phonemes, this transcription provides a set of 3-letter feature abbreviations allowing a phoneme to be described as a sequence of features.

This document extends Evan Kirshenbaum’s feature set to be able to describe the different phonemes in the IPA and as are used in the various languages of the world. The origin column is used to describe where the feature originated from:

1. `kirshenbaum` – The feature originated from Evan Kirshenbaum’s ASCII-IPA Feature Abbreviation table in Appendix A of his ASCII-IPA document [1], [2].
2. `cainteoir` – The feature originated from the Cainteoir Text-to-Speech phoneme features [5].
3. `espeak-ng` – The features originate from the eSpeak NG Text-to-Speech program, and are defined in this document.

Not all the Cainteoir Text-to-Speech phoneme features are listed here, only the ones that are relevant to eSpeak NG.

The goal of this document is not to provide a detailed guide on phonetics. Nor is it intended to be able to accurately record differences in IPA diacritics. Instead, it is designed to be a transcription guide for authors of espeak-ng languages and voices on how to specify phonemes so that the IPA and feature transcriptions are consistent.

## Phoneme Transcription Schemes

BCP47 Subtag | Abbreviation | Transcription Scheme | Encoding
--- | --- | --- | ---
`fonipa` | IPA | International Phonetic Alphabet | Unicode
`fonxsamp` | X-SAMPA | Extended Speech Assessment Methods Phonetic Alphabet | ASCII
`x-foncxs` | CXS | Conlang X-SAMPA | ASCII
`x-fonkirsh` |  | Kirshenbaum (ASCII-IPA) | ASCII

1. `foncxs` and `fonkirsh` are private use extensions defined in the bcp47-extensions file, so have the `x-` private use specifier before their subtag names.

## Consonants

| `blb` |  | `lbd` |  | `dnt` |  | `alv` |  | `pla` |  | `rfx` |  | `alp` |  | `pal` |  | `vel` |  | `uvl` |  | `phr` |  | `glt` |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
| `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd`
`nas` | m̥ | m |  | ɱ |  |  | n̥ | n |  |  | ɳ̊ | ɳ | ɲ̟̊ | ɲ̟ | ɲ̊ | ɲ | ŋ̊ | ŋ | ɴ̥ | ɴ |  |  |  |
`stp` | p | b | p̪ | b̪ | t̪ | d̪ | t | d |  |  | ʈ | ɖ |  |  | c | ɟ | k | ɡ | q | ɢ | ʡ |  | ʔ |
`sib` `afr` |  |  |  |  |  |  | t͡s | d͡z | t͡ʃ | d͡ʒ | ʈ͡ʂ | ɖ͡ʐ | t͡ɕ | d͡ʑ |  |  |  |  |  |  |  |  |  |
`afr` | p͡ɸ | b͡β | p̪͡f | b̪͡v | t͡θ | d͡ð |  |  |  |  |  |  |  |  | c͡ç | ɟ͡ʝ | k͡x | ɡ͡ɣ | q͡χ | ɢ͡ʁ | ʡ͡ħ | ʡ͡ʕ | ʔ͡h |
`lat` `afr` |  |  |  |  |  |  | t͡ɬ | d͡ɮ |  |  | ʈ͡ɭ̊˔ |  |  |  | c͡ʎ̥˔ |  | k͡ʟ̝̊ | ɡ͡ʟ̝ |  |  |  |  |  |
`sib` `frc` |  |  |  |  |  |  | s | z | ʃ | ʒ | ʂ | ʐ | ɕ | ʑ |  |  |  |  |  |  |  |  |  |
`frc` | ɸ | β | f | v | θ | ð |  |  |  |  |  |  |  |  | ç | ʝ | x | ɣ | χ | ʁ | ħ | ʕ | h | ɦ
`lat` `frc` |  |  |  |  |  |  | ɬ | ɮ |  |  | ɭ̊˔ |  |  |  | ʎ̥˔ | ʎ̝ | ʟ̝̊ | ʟ̝ |  |  |  |  |  |
`apr` |  |  | ʋ̥ | ʋ |  |  | ɹ̥ | ɹ |  |  | ɻ̊ | ɻ |  |  | j̊ | j | ɰ̊ | ɰ |  |  |  |  |  |
`lat` `apr` |  |  |  |  |  |  | l̥ | l |  |  | ɭ̊ | ɭ |  |  | ʎ̥ | ʎ | ʟ̥ | ʟ |  | ʟ̠ |  |  |  |
`flp` |  | ⱱ̟ |  | ⱱ |  |  | ɾ̥ | ɾ |  |  | ɽ̊ | ɽ |  |  |  |  |  |  |  | ɢ̆ |  | ʡ̮ |  |
`lat` `flp` |  |  |  |  |  |  |  | ɺ |  |  |  | ɭ̆ |  |  |  | ʎ̮ |  | ʟ̆ |  |  |  |  |  |
`trl` |  | ʙ |  |  |  |  | r̥ | r |  |  | ɽ͡r̥ | ɽ͡r |  |  |  |  |  |  | ʀ̥ | ʀ | ʜ | ʢ |  |
`clk` | ʘ |  |  |  | ǀ |  | ǃ |  |  |  |  |  | ǂ |  |  |  |  |  |  |  |  |  |  |
`lat` `clk` |  |  |  |  |  |  | ǁ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
`imp` |  | ɓ |  |  |  |  |  | ɗ |  |  |  |  |  |  |  | ʄ |  | ɠ |  | ʛ |  |  |  |
`ejc` | pʼ |  |  |  |  |  | tʼ |  |  |  | ʈʼ |  |  |  | cʼ |  | kʼ |  | qʼ |  | ʡʼ |  |  |
`ejc` `frc` |  |  | fʼ |  | θʼ |  | sʼ |  | ʃʼ |  | ʂʼ |  |  |  |  |  | xʼ |  | χʼ |  |  |  |  |
`lat` `ejc` `frc` |  |  |  |  |  |  | ɬʼ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

### Other Symbols

| `bld` |  | `alv` |  | `pla` |  | `pal` |  | `lbv` |  | `vel` |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
| `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd` | `vls` | `vcd`
`nas` |  |  |  |  |  |  |  |  |  | ŋ͡m |  |
`stp` |  |  |  |  |  |  |  |  | k͡p | ɡ͡b |  |
`afr` | p͡f | b͡v |  |  |  |  |  |  |  |  |  |
`vzd` `frc` |  |  |  |  | ɧ |  |  |  |  |  |  |
`ptr` `apr` |  |  |  |  |  |  |  | ɥ |  |  | ʍ | w
`fzd` `lat` `apr` |  |  |  | ɫ |  |  |  |  |  |  |  |

### Gemination

Gemination is found in several languages including Italian and Japanese. It is also present in the suprasegmental phonology between words such as “lamppost” and “evenness”.

Some linguists use the long suprasegmental for geminate consonants. The eSpeak NG convention is to use consonant length for phonation when consonant length is distinct without gemination occurring.

The way gemination is represented in eSpeak NG is to duplicate the phonemes, with the first phoneme using the `unx` feature. For example, n̚.n for a geminated n. This describes how with the `stp` and `nas` consonants, the mouth remains closed (`unx`) for the first of the geminated consonants.

### Manner of Articulation

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`nas` |  | nasal | `kirshenbaum`
`stp` |  | plosive (stop) | `kirshenbaum`
`afr` |  | affricate | `espeak-ng`
`frc` |  | fricative | `kirshenbaum`
`flp` |  | tap/flap | `kirshenbaum`
`trl` |  | trill | `kirshenbaum`
`apr` |  | approximant | `kirshenbaum`
`clk` |  | click | `kirshenbaum`
`ejc` | ◌ʼ | ejective | `kirshenbaum`
`imp` |  | implosive | `kirshenbaum`
`vwl` |  | vowel | `kirshenbaum`

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.

NOTE: Evan Kirshenbaum defines an `orl` (oral) feature which is not used. From context, it looks like `{orl,stp}` was indended to be used for plosives, and `{nas,stp}` for nasals. That feature is not defined in this document, but is defined in the phoneme model.

The manner of articulation can be refined using the following features:

Feature | Name | Origin
--- | --- | ---
`lat` | lateral | `kirshenbaum`
`sib` | sibilant | `cainteoir`

NOTE: Evan Kirshenbaum defines a `ctl` (central) feature which is not used. From context, it looks like it was intended to explicitly annotate consonants as having a central release, similar to how the `lat` feature is used for lateral release. As consonants are implicitly central, the `ctl` feature is not needed and as such is not defined in this document.

### Place of Articulation

Feature | Name | Origin
--- | --- | ---
`blb` | bilabial | `kirshenbaum`
`lbd` | labio-dental | `kirshenbaum`
`bld` | bilabial-labio-dental | `espeak-ng`
`dnt` | dental | `kirshenbaum`
`alv` | alveolar | `kirshenbaum`
`pla` | palato-alveolar | `kirshenbaum`
`rfx` | retroflex | `kirshenbaum`
`alp` | alveolo-palatal | `cainteoir`
`pal` | palatal | `kirshenbaum`
`vel` | velar | `kirshenbaum`
`lbv` | labio-velar | `kirshenbaum`
`uvl` | uvular | `kirshenbaum`
`phr` | pharyngeal | `kirshenbaum`
`glt` | glottal | `kirshenbaum`

The `bld` place of articulation is used for `afr` consonants that have a `blb` onset and a `lbd` release, e.g. in the German p͡f consonant.

NOTE: The IPA charts make a distinction between pharyngeal and epiglottal consonants, but Wikipedia does not. This model uses the Wikipedia descriptions.

### Voice

Feature | Name | Origin
--- | --- | ---
`vls` | voiceless | `kirshenbaum`
`vcd` | voiced | `kirshenbaum`

## Vowels

| `fnt` |  | `cnt` |  | `bck` |
--- | --- | --- | --- | --- | --- | ---
| `unr` | `rnd` | `unr` | `rnd` | `unr` | `rnd`
`hgh` | i | y | ɨ | ʉ | ɯ | u
`smh` | ɪ | ʏ |  |  |  | ʊ
`umd` | e | ø | ɘ | ɵ | ɤ | o
`mid` |  |  | ə |  |  |
`lmd` | ɛ | œ | ɜ | ɞ | ʌ | ɔ
`sml` | æ |  | ɐ |  |  |
`low` | a | ɶ |  |  | ɑ | ɒ

### Other Symbols

Symbol | Features
--- | ---
ɚ | `unr` `mid` `cnt` `rzd` `vwl`
ɝ | `unr` `lmd` `cnt` `rzd` `vwl`

### Height

Feature | Name | Origin
--- | --- | ---
`hgh` | close (high) | `kirshenbaum`
`smh` | near-close (semi-high) | `kirshenbaum`
`umd` | close-mid (upper-mid) | `kirshenbaum`
`mid` | mid | `kirshenbaum`
`lmd` | open-mid (lower-mid) | `kirshenbaum`
`sml` | near-open (semi-low) | `cainteoir`
`low` | open (low) | `kirshenbaum`

### Backness

Feature | Name | Origin
--- | --- | ---
`fnt` | front | `kirshenbaum`
`cnt` | center | `kirshenbaum`
`bck` | back | `kirshenbaum`

NOTE: The `smh` vowels are more `cnt` than the other vowels. However, this distinction is not needed to classify these vowels so there are no features for front-central and back-central. The `fnt` and `bck` features are used instead.

### Rounding

Feature | Name | Origin
--- | --- | ---
`unr` | unrounded | `kirshenbaum`
`rnd` | rounded | `kirshenbaum`

## Diacritics

### Articulation

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`lgl` | ◌̼ | linguolabial | `cainteoir`
`idt` | ◌̪͆ | interdental | `espeak-ng`
| ◌̪ | dental |
`apc` | ◌̺ | apical | `espeak-ng`
`lmn` | ◌̻ | laminal | `cainteoir`
| ◌̟ | advanced |
| ◌̠ | retracted |
| ◌̈ | centralized |
| ◌̽ | mid-centralized |
| ◌̝ | raised |
| ◌̞ | lowered |

The articulations that do not have a corresponding feature name are recorded using the features of their new location in the consonant or vowel charts, not using the features of the base phoneme.

### Air Flow

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`egs` | ↑ | egressive | `espeak-ng`
`igs` | ↓ | ingressive | `espeak-ng`

The ↑ and ↓ symbols are from the extended IPA[7]. They only need to be used when the air flow is different to the base IPA phoneme (e.g. using ↓ on pulmonic consonants).

### Phonation

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`brv` | ◌̤ | breathy voice | `espeak-ng`
`slv` | ◌̥ | slack voice | `cainteoir`
`stv` | ◌̬ | stiff voice | `cainteoir`
`crv` | ◌̰ | creaky voice | `cainteoir`
`glc` | ʔ͡◌ | glottal closure | `espeak-ng`

The IPA ◌̥ diacritic is also used to fill the `vls` spaces in the IPA consonant charts. Thus, when ◌̥ is used with a `vcd` consonant that does not have an equivalent `vls` consonant, the resulting consonant is `vls`, not `slv`.

NOTE: Evan Kirshenbaum uses the `mrm` (murmured) feature for breathy voice, using it for `[ɦ]` instead of `vcd`, following the way the phoneme is pronounced instead of how it is annotated on the IPA chart.

### Rounding and Labialization

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`ptr` | ◌ʷ, ◌ᶣ | protruded | `espeak-ng`
`cmp` | ◌ᵝ | compressed | `espeak-ng`

NOTE: Evan Kirshenbaum uses the `lzd` (labialized) feature for protruded.

The degree of rounding/labialization can be specified using the following features:

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`mrd` | ◌̹ | more rounded | `cainteoir`
`lrd` | ◌̜ | less rounded | `cainteoir`

### Syllabicity

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`syl` | ◌̩ | syllabic | `kirshenbaum`
`nsy` | ◌̯ | non-syllabic | `cainteoir`

### Consonant Release

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`asp` | ◌ʰ | aspirated | `kirshenbaum`
`nrs` | ◌ⁿ | nasal release | `espeak-ng`
`lrs` | ◌ˡ | lateral release | `espeak-ng`
`unx` | ◌̚ | no audible release (unexploded) | `kirshenbaum`

### Co-articulation

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`pzd` | ◌ʲ | palatalized | `kirshenbaum`
`vzd` | ◌ˠ, ◌̴ | velarized | `kirshenbaum`
`fzd` | ◌ˤ, ◌̴ | pharyngealized | `kirshenbaum`
`nzd` | ◌̃ | nasalized | `kirshenbaum`
`rzd` | ◌˞ | rhoticized | `kirshenbaum`

The combining ◌̴ mark is used for velarized or pharyngealized consonants. Wikipedia recommends precomposed letters for this as this combining mark is deprecated, and the font may not render the composed form correctly.

### Tongue Root

The tongue root position can be specified using the following features:

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`atr` | ◌̘ | advanced tongue root | `cainteoir`
`rtr` | ◌̙ | retracted tongue root | `cainteoir`

### Fortis and Lenis

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`fts` | ◌͈ | fortis | `espeak-ng`
`lns` | ◌͉ | lenis | `espeak-ng`

The extended IPA[7] ◌͈ and ◌͉ diacritics are used to specify lesser (`lns`) and greater (`fts`) oral pressure than the unmodified voiced or voiceless phoneme. This distinction is made by the Ewe, Tabasaran, Archi, and other languages[8].

Where fortis and lenis are used to contrast consonant durations (e.g. in the Jawoyn, Ojibwe, and Zurich German languages[8]), the length suprasegmentals are used instead.

## Suprasegmentals

### Stress

Symbol | Name
--- | ---
`ˈ◌` | primary stress
`ˌ◌` | secondary stress

### Length

Feature | Symbol | Name | Origin
--- | --- | --- | ---
`est` | ◌̆ | extra short | `cainteoir`
`hlg` | ◌ˑ | half-long | `cainteoir`
`lng` | ◌ː | long | `kirshenbaum`
`elg` | ◌ːː | extra long | `espeak-ng`

### Rhythm

Symbol | Name
--- | ---
`.` | syllable break
`◌‿◌` | linking (no break)

### Tones

Symbol | Name
--- | ---
`◌˥` | extra high tone
`◌˦` | high tone
`◌˧` | mid tone
`◌˨` | low tone
`◌˩` | extra low tone
`ꜛ◌` | upstep
`ꜜ◌` | downstep

### Intonation

Symbol | Name
--- | ---
`|` | minor (foot) break
`‖` | major (intonation) break
`↗︎` | global rise
`↘︎` | global fall

## 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. Dunn, R. H., Cainteoir Text-to-Speech Phoneme Features. 2013-2015.

6. Wikipedia. Voiced glottal fricative. 2017, Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA).

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

8. Wikipedia. Fortis and lenis. 2017, Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA).

9. Wikipedia. Place of articulation. 2017, Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA).