APPLICATION DICTIONARY
DECtalk PC has memory allocated for a loadable dictionary. This dictionary is useful in cases where (a) DECtalk makes an error in pronounciation, or (b) the pronunciation of a string is unique to the application. For example, if the sequence n/cl should be pronounced as "not cleared", then a user dictionary entry is obviously needed.

NOTE: To utilize the capabilities of the Application Dictionary requires the abilty to convert words into their phonemic equivalent. An analogy of this would be in most dictionaries where the phonemic equivalent follows each word entry.

To create and load a dictionary to DECtalk PC, you must do the following:

1. Create a dictionary table file using a text editor. The dictionary must be in the following format:

(a) An entry must start at the first character of the line. Any space or illegal character as the first character of the line causes the line to be treated as a comment and it will therefore not be processed.

(b) The syntax is:

string-to-be-pronounced [phonemic substitution]

Each line may be up to 256 characters long.

(c) A string is comprised of legal characters. Legal characters are:

The letters A-Z and a-z, the numbers 0-9 and
select punctuation marks such as ", !, @, &, (, ), -, \, and /.

NOTE: The punctuation mark characters may not be used at the beginning of the character string.

The letters may be in either upper or lower case.

Uppercase letters match only upper case; lowercase letters match either uppercase or lowercase.

(d) The phoneme string is comprised of legal phonemes as listed in the following section, "DECtalk Phonemic Symbols".

Phonemes are always in square brackets but may be in either upper or lower case.

For example, to make the word "coffee" be pronounced as "tea", you would enter the following:

coffee [t'iy]

2. After creating your dictionary table file, you compile into a dictionary file by typing a command in the following format:

user_dic input dictionary table output dictionary file

Input files have the default extension of ".tab" but any extension can be used.

Output dictionary files have the extension of ".dtu" and must have that extension for the loader to find the file correctly. If no output file is specified, a file with the same name and .dtu extension will be created for the output.

For example: if your dictionary table is called mydict.tab, type:

user_dic mydict

In this case, the input dictionary table file called mydict.tab would be compiled into a new output dictionary file called mydict.dtu.

3. Load the user dictionary by switching to the DECtalk file subdirectory and typing:

dt_load output file.dtu

For example, you would type:

dt_load mydict.dtu

Your customized dictionary is now loaded and ready for use.

Suffix Handling

User dictionary lookups are done after suffix stripping occurs. Therefore, inflected and derived forms of words should also be pronounced according to the dictionary entry. For example if the word "rocket" was put into the dictionary table then the words "rockets", "rocketed" and "rocketing" would be pronounced according to the phonemic entry for the root word.with the proper suffix attached.

Reloading Dictionaries

The User dictionary can not be loaded onto the board more than once without first restarting either the DECtalk PC or rebooting the machine.

Warning: If your PC is powered down, you must reload the user dictionary at power-up. To have a user dictionary loaded each time the PC is powered up, the compiled file name should be added to the end of the DT_LOAD command string in the DECtalk BAT file. For example in the DT.BAT file for DECtalk PC, DT2.BAT for the DECtalk PC2 and in the DTEXP.BAT for the DECtalk Express.

DECtalk PHONEMIC SYMBOLS
Several English phonemic alphabets are widely used today. The Table below lists the phonemic alphabets that DECtalk uses, along with an example of each sound. Some dictionaries put the stress symbol after the vowel nucleus or at the start of the syllable. DECtalk requires that the stress symbol appear immediately before the vowel.

MULTI-CHARACTER ALPHABET -
For USER DICTIONARY and PHONETIC Modifications to TEXT
Vowels
Phonemic Example
Symbol

ey bake

aa Bob

iy beat

eh bet

ay bite

ih bit

oy boy

ow boat

uw lute

ah but

aw bout

yu cute

rr bird

ao bought

ae bat

uh book

ix kisses

ax about

Consonants
Phonemic Example
Symbol

p pet
b bet
t test
d debt
k Ken
g guess
f fin
v vest
th thin
dh this
s sit
z zoo
sh shin
zh measure
ch chin
jh gin
m met
n net
nx sing
w wet
y yet
hx head
r red
l let
el bottle
en button

Note: the [em] phoneme in the early version of DECtalk is no longer valid but can be replaced with the sequence [axm].

Allophones

rx oration (postvocalic r)
lx electric (postvocalic l)
q we eat (glottal stop)
dx rider (flap d)
tx Latin (glottalized t)