Dictionary English: UK/USA vs USA legal (what is the difference?)

[ittvangergo]

In InDesign I need a good dictionary for good hyphenation.

In terms of hyphenation I see no differences between UK and USA. 

But I see an obvious difference between the two above and USA legal. 

The same way as online hyphenator sites are differ too. 

For example

UK and USA hyphen like this: 

• add-ed
• broth-el
• ex-cep-tion-al

USA legal like this:

• added
• brothel
• ex-cep-tional

Can someone give me some enlightment why is there a difference and what is this difference? Of course it is subjective but which is senior to the other? And in what aspect?

I need to decide which to choose over the other in the typesetting of a novel. 

This is more grammatical question then InDesign one but I hope some people are already ahead of me in this journey. 

[Brad @ Roaring Mouse · Accepted solution]

In a nutshell, the spelling dictionaries and hypehantion dictionaries (if any) that InDesign uses are Open Source from Hunspell; many other programs besides Adobe's use them. Not all languages have hyphenation dictionaries that are tuned for that particular language; the ones that don't rely on a more generic hyphenation algorithm. I don't see one for US Legal or US Medical, so that's probably working against you. In any case, you can still disgaree with what Hunspell says the hyphenation should be for a particular word, but you can add those to your User dictionary accordingly.

[ittvangergo]

Dear Brad, 

Your summary is very valuable and this is a really smart approach. Thank you!