How is a hyphenation dictionary used for hyphenation?

Question

I've read about hyphenation and I came to know that the hyphenation depends on the dictionary, we are using for the particular language. For some words Microsoft Office hyphenates differently than LibreOffice. I tried to open the dictionaryhyph_en_US.dic but couldn't understand the content. What I didn't get is, how the dictionary is used.

1. Does it contain the list of words to hyphenate?
2. Does it contain the rules to decide as to how to hyphenate the word?

Note: I know they use algorithms as well to make the hyphenation better but to what extent does the dictionary play a role?

Any help will be much appreciated.

Regards, Ankur Vashishtha

Answer 1

LibreOffice like TeX and a lot of other programs use the hyphenation algorithm created by Franklin M. Liang. This algorithm uses a pattern matching technique to find hyphenation points in words. A separate dictionary file containing the patterns is used for each language. According to Franklin M. Liang's thesis:

These patterns find 89% of the hyphens in a pocket dictionary word list, with essentially no error.

As to how Word does it, it is hard to tell, since it is proprietary software. My guess is that it does not use such an algorithm but a real dictionary with the 100% correct hyphenation points added in. This would explain why the hyphenation is different and more accurate in Word.