Computer method and apparatus for text-to-speech synthesizer dictionary reduction

A method for reducing the size of a dictionary used in a speech synthesis system having a set of rules for determining phonemes from graphemes, the dictionary containing a plurality of entries, each entry comprising a grapheme string and a corresponding phoneme string, the method comprising the steps of:

• for each entry in the dictionary, determining if the entry in the dictionary can be fully matched by using rules of the rule set, and if so, indicating the entry to be deleted from the dictionary;
• and
• creating a reduced dictionary from the entries remaining after omitting any entries indicated as to be deleted;
• wherein each entry comprises a grapheme string and a corresponding phoneme string.

A method for reducing the size of a dictionary used in a speech synthesis system having a set of rules for determining phonemes from graphemes, the dictionary containing a plurality of entries, each entry comprising a grapheme string and a corresponding phoneme string, the method comprising the steps of:

• for each entry in the dictionary, determining if the entry in the dictionary can be fully matched by using rules of the rule set, and if so, indicating the entry to be deleted from the dictionary including the steps of:
• generating a rule-based phoneme string for the gapheme string of the entry using rules in the rule set;
• and
• determining if the rule-based phoneme string matches the corresponding phoneme string of the entry, and if so, indicating the entry to be deleted from the dictionary;
• creating a reduced dictionary from the entries remaining after omitting any entries indicated as to be deleted;
• providing an affix rule set for the speech synthesis system, the affix rule set for determining phonemes from beginning and ending graphemes of character strings;
• and
• before generating a rule based phoneme string, checking if any affix rule from the affix rule set matches a portion of the grapheme string of the entry, and if so, skipping to a next entry in the dictionary for processing;
• wherein the step of determining if an entry in the dictionary can be fully matched, is performed for each entry in the dictionary starting with a first entry.

A method for reducing the size of a dictionary used in a speech synthesis system, the dictionary containing a plurality of entries, each entry comprising a grapheme string and a corresponding phoneme string, the method comprising the steps of:

• determining if a given entry is required in the dictionary in order to produce the phoneme string of another entry, and if so, indicating the given entry to be saved;
• and
• creating a dictionary containing entries indicated to be saved;
• and
• wherein the speech synthesis system includes an affix rule set containing affix rules for determining phonemes from beginning and ending graphemes of character strings, each affix rule having a grapheme portion and a corresponding phoneme portion;
• and
• the step of determining if the given entry is required in the dictionary includes the steps of:
• combining grapheme and phoneme strings of a root word entry in the dictionary with respective grapheme and phoneme portions of an affix rule of the affix rule set to form a grapheme combination and phoneme combination pair;
• and
• determining if the grapheme combination and phoneme combination pair exists as a matching entry in the dictionary, and if so, indicating the root word entry to be saved in the dictionary and indicating the matching entry to be deleted.

A method for reducing the size of a dictionary used in a speech synthesis system having a set of rules for determining phonemes from gaphemes, the dictionary containing a plurality of entries, each entry comprising a grapheme string and a corresponding phoneme string, the method comprising the steps of:

• determining if a given entry in the dictionary can be fully matched by using rules of the rule set, and if so, indicating the entry to be deleted from the dictionary including the steps of:
• generating a rule-based phoneme string for the grapheme string of the entry using rules in the rule set;
• and
• determining if the rule-based phoneme string matches the corresponding phoneme string of the entry, and if so, indicating the entry to be deleted from the dictionary;
• determining if the given entry is required in the dictionary in order to support other entries, and if so, indicating the given entry to be saved;
• and
• aggregating the entries indicated as to be saved, to form a reduced dictionary therefrom.