A phoneme table defines all the phonemes which are used by a language, together with their properties and the data for their production as sounds.
Generally each language has its own phoneme table, although additional phoneme tables can be used for different voices within the language. These alternatives are referenced from Voice files.
A phoneme table does not need to define all the phonemes used by a language. It can inherit the phonemes from a previously defined phoneme table. For example, a phoneme table may redefine (or add) some of the vowels that it uses, but inherit most of its consonants from a standard set.
The source files for the phoneme data are in the “phsource” directory in the espeakedit download package. “Vowel files”, which are referenced in FMT(), VowelStart(), and VowelEnding() instructions are made using the espeakedit program.
The phoneme tables are defined in a master phoneme file, named phonemes. This starts with the base phoneme table followed by phoneme tables for other languages and voices. These inherit phonemes from the base table or previously defined tables.
In addition to phoneme definitions, the phoneme file can contain the following:
Note: These new Phoneme definitions apply to eSpeak NG version 420 and later.
A phoneme table contains a list of phoneme definitions. Each starts with the keyword phoneme and the phoneme name (this is the name used in the pronunciation rules in a language’s *_rules and *_list files), and ends with the keyword endphoneme. For example:
phoneme aI
vowel
starttype #a endtype #i
length 230
FMT(vowels/ai)
endphoneme
phoneme s
vls alv frc sibilant
voicingswitch z
lengthmod 3
Vowelin f1=0 f2=1700 -300 300 f3=-100 80
Vowelout f1=0 f2=1700 -300 250 f3=-100 80 rms=20
IF nextPh(isPause) THEN
WAV(ufric/s_)
ELIF nextPh(p) OR nextPh(t) OR nextPh(k) THEN
WAV(ufric/s!)
ENDIF
WAV(ufric/s)
endphoneme
A phoneme definition contains both static properties and executed instructions. The instructions may contain conditional statements, so that the effect of the phoneme may be different depending on adjacent phonemes, whether the syllable is stressed, etc.
The instructions of a phoneme are interpreted in two different phases. In the first phase, the instructions may change the phoneme and replace it by a different phoneme. In the second phase, instructions are used to produce the sound for the phoneme.
The import_phoneme statement can be used to copy a previously defined phoneme from a specified phoneme table. For example:
phoneme t
import_phoneme base/t[
endphoneme
means: phoneme t
in this phoneme table is a copy of
phoneme t[
from phoneme table “base”. A length
instruction can be used after import_phoneme to vary the length
from the original.
Within the phoneme definition the following lines may occur: ( (V) indicates only for vowels, © only for consonants)
Type. One of these must be present.
Type | Description |
---|---|
vowel | |
liquid | semi-vowels, such as: r, l, j, w |
nasal | nasal eg: m, n, N |
stop | stop eg: p, b, t, d, k, g |
frc | fricative eg: f, v, T, D, s, z, S, Z, C, x |
afr | affricate eg: tS, dZ |
pause | |
stress | used for stress symbols, eg: ‘ , = % |
virtual | Used to represent a class of phonemes. |
Properties:
Property | Description |
---|---|
vls | © voiceless eg. p, t, k, f, s |
vcd | © voiced eg. b, d, g, v, z |
sibilant | © eg: s, z, S, Z, tS, dZ |
palatal | © A palatal or palatalized consonant. |
rhotic | © An “r” type consonant. |
unstressed | (V) This vowel is always unstressed, unless explicitly marked otherwise. |
nolink | Prevent any linking from the previous phoneme. |
nopause | Used in a liquid or nasal phoneme to prevent eSpeak inserting a short pause if a word starts with this phoneme and the previous word ends with a vowel. |
trill | (C) Apply trill to the voicing. |
Place of Articulation ©:
Articulation | Description |
---|---|
blb | bi-labial |
ldb | labio-dental |
dnt | dental |
alv | alveolar |
rfx | retroflex |
pla | palato-alveolar |
pal | palatal |
vel | velar |
lbv | labio-velar |
uvl | uvular |
phr | pharyngeal |
glt | glottal |
starttype <phoneme>
Allocates this phoneme to a group so that conditions such as nextPh(#e) can test for any of a group of phonemes. Pre-defined groups for use for vowels are: #@ #a #e #i #o #u. Additional groups can be defined as phonemes with type “virtual”.
endtype <phoneme>
Allocates this phoneme to a group so that conditions such as prevPh(#e) can test for any of a group of phonemes. Pre-defined groups for use for vowels are: #@ #a #e #i #o #u. Additional groups can be defined as phonemes with type “virtual”.
lengthmod <integer>
(C) Determines how this consonant affects the length of the previous vowel.
This value is used as index into the length_mods
table in the CalcLengths()
function in the eSpeak program.
voicingswitch <phoneme>
This is used for some languages to change between voiced and unvoiced phonemes.
Phoneme Instructions may be included within conditional statements.
During the first phase of phoneme interpretation, an instruction which causes a change to a different phoneme will terminate the instructions. During the second phase, FMT() and WAV() instructions will terminate the instructions.
length <length>
The relative length of the phoneme, typically about 140 for a short vowel and from 200 to 300 for a long vowel or diphong. A length() instruction is needed for vowels. It is optional for consonants.
ipa <ipa string>
In many cases, eSpeak makes IPA (International Phonetic Alpbabet) phoneme names automatically from eSpeak phoneme names. If this is not correct, then the phoneme definition can include an ipa instruction to specify the correct IPA name. IPA strings may include non-ascii characters. They may also include characters specified by their character codes in the form U+ followed by 4 hexadecimal digits. For example a string: aU+0303 indicates ‘a’ with a ‘combining tilde’.
WAV(<wav file>, <amplitude>)
<wav file> is a path to a WAV file (22 kHz, 16 bits, mono) within phsource/
which will be played to produce the sound. This method is used for unvoiced consonants. <wavefile> does not include a .WAV filename extension, although the file to which it refers may or may not have one.
<amplitude> is optional. It is a percentage change to the amplitude of the WAV file. So, WAV(ufric/s, 50)
means: play file ‘ufric/s.wav’ at 50% amplitude.
FMT(<vowel file>, <amplitude>)
<vowel file> is a path to a file (within phsource/
) which defines how to generate the sound (a vowel or voiced consonant) from a sequence of formant values. Vowel files are made using the espeakedit program.
<amplitude> is optional. It is a percentage change to the amplitude of the sound which is synthesized from the FMT() instruction.
FMT(<vowel file>, <amplitude>) addWav(<wav file>, <amplitude>)
For voiced consonants, a FMT() instruction may be followed by an addWav() instruction. addWav() has the same format as a WAV() instruction, but the WAV file is mixed with the sound which is synthesized from the FMT() instruction.
VowelStart(<vowel file>, <length adjust>)
This is used to modify the start of a vowel when it follows a sonorant consonant (such as [l] or [j]). It replaces the first frame of the <vowel file> which is specified in a FMT() instruction by this <vowel file>, and adjusts the length of the original by a signed value <length adjust>. The VowelStart() instruction may be specified either in the phoneme definition of the vowel, or in the phoneme definition of the sonorant consonant which precedes the vowel. The former takes precedence.
VowelEnding(<vowel file>, <length adjust>)
This is used to modify the end of a vowel when it is followed by a sonorant consonant (such as [l] or [j]). It is appended to the <vowel file> which is specified in a FMT() instruction by this <vowel file>, and adjusts the length of the original by a signed value <length adjust>. The VowelEnding() instruction may be specified either in the phoneme definition of the vowel, or in the phoneme definition of the sonorant consonant which follows the vowel. The former takes precedence.
Vowelin <vowel transition data>
© Specifies the effects of this consonant on the formants of a following vowel. See “vowel transitions”, below.
Vowelout <vowel transition data>
© Specifies the effects of this consonant on the formants of a preceding vowel. See “vowel transitions”, below.
ChangePhoneme(<phoneme>)
Change to the specified phoneme.
ChangeIfDiminished(<phoneme>)
Change to the specified phoneme (such as schwa, @) if this syllable has “diminished” stress.
ChangeIfUnstressed(<phoneme>)
Change to the specified phoneme if this syllable has “diminished” or “unstressed” stress.
ChangeIfNotStressed(<phoneme>)
Change to the specified phoneme if this syllable does not have “primary” stress.
ChangeIfStressed(<phoneme>)
Change to the specified phoneme if this syllable has “primary” stress.
IfNextVowelAppend(<phoneme>)
If the following phoneme is a vowel then this additional phoneme will be inserted before it.
RETURN
Ends executions of instructions.
CALL <phoneme table>/<phoneme>
Executes the instructions of the specified phoneme.
Phoneme definitions can contain conditional statements such as:
<pre> IF <condition> THEN
<statements>
ENDIF
</pre>
or more generally:
<pre> IF <condition> THEN
<statements>
ELIF <condition> THEN
<statements>
...
ELSE
<statements>
ENDIF
</pre>
where the ELSE
and multiple ELSE
parts are optional.
Multiple conditions may be joined with AND
or OR
, but not a mixture of AND
s and OR
s.
A condition may be preceded by NOT
. For example:
<pre> IF <condition> AND NOT <condition> THEN
<statements>
ENDIF
</pre>
Conditions can be:
thisPh(<attribute>)
Test this current phoneme
prevPh(<attribute>) Test the previous phoneme
prevPhW(<attribute>) Test the previous phoneme, but only within the same word. Returns false if there is no previous phoneme in the word.
prev2PhW(<attribute>) Test the phoneme before the previous phoneme, but only within the same word. Returns false if it is not in this word.
nextPh(<attribute>) Test the following phoneme
next2Ph(<attribute>) Test the phoneme after the next phoneme.
nextPhW(<attribute>) Test the next phoneme, but only within the same word. Returns false if there is no following phoneme in the word.
next2PhW(<attribute>) Test the phoneme after the next phoneme, but only within the same word. Returns false if not found before the word end.
next3PhW(<attribute>) Test the third phoneme after the current phoneme, but only within the same word. Returns false if not found before the word end.
nextVowel(<attribute>) Test the next vowel after the current phoneme, but only within the same word. Returns false if there is none.
prevVowel(<attribute>) Test the previous vowel before the current phoneme, but only within the same word. Returns false if there is none.
PreVoicing() This is used as part of the instructions for voiced stop consonants (eg. [d] [g]). If true then produce a voiced murmur before the stop.
KlattSynth() Returns true if the voice is using the Klatt synthesizer rather than the eSpeak synthesizer.
Note: Additional attributes could be added to eSpeak if needed.
True if the phoneme has this phoneme name.
<phoneme name>
True if the phoneme has this phoneme name.
<phoneme group>
True if the phoneme has this starttype (or if it has this endtype if it’s used in prevPh() ). The pre-defined phoneme groups are #@, #a, #e, #i, #o, #u.
isPause True if the phoneme is a pause.
isPause2
nextPh(isPause2)
is used to test whether the next phoneme is not a vowel or liquid consonant within the same word.
isVowel
isNotVowel
isLiquid
isNasal
isVFricative
These test the phoneme type.
isPalatal
isRhotic
These test whether the phoneme has this property.
isWordStart
notWordStart
isWordEnd
True if this is the final phoneme in a word.
isFirstVowel
isSecondVowel
isFinalVowel
isAfterStress
True if this phoneme is after the stressed vowel in a word.
isVoiced
True if this phoneme is a vowel or a voiced consonant.
isDiminished
True if the syllable stress is “diminished”
isUnstressed
True if the syllable stress is “diminished” or “unstressed”
isNotStressed
True if the syllable stress is not “primary stress”.
isStressed True if the syllable stress is “primary stress”.
isMaxStress
True if this is the highest stressed syllable in the word.
There are three ways to produce sounds:
[p] [t] [s]
.[l] [j] [n]
.[b] [g] [v] [z]
.These specify how a consonant affects an adjacent vowel. A consonant may cause a transition in the vowel’s formants as the mouth changes shape between the consonant and the vowel. The following attributes may be specified. Note that the maximum rate of change of formant frequencies is limited by the speak program.
len=
Nominal length of the transition in mS. If omitted a default value is used.
rms=
Adjusts the amplitude of the vowel at the end of the transition. If omitted a default value is used.
f1=
0: f1 formant frequency unchanged.
1: f1 formant frequency decreases.
2: f1 formant frequency decreases more.
f2=
<freq>: The frequency towards which the f2 formant moves (Hz).
<min>: Signed integer (Hz). The minimum f2 frequency change.
<max>: Signed integer (Hz). The maximum f2 frequency change.
f3=
<change>: Signed integer (Hz). Frequence change of f3, f4, and f5 formants.
<amplitude>: Amplitude of the f3, f4, and f5 formants at the end of the transition. 100 = no change.
brk
Break. Do not merge the synthesized wave of the consonant into the vowel. This will produce a discontinuity in the formants.
rate
Allow a greater maximum rate of change of formant frequencies.
glstop
Indicates a glottal stop.