Mozilla spellcheck options

[Temlakos]

Everyone:

Where is the English-US option for default spelling dictionaries in 
Firefox and Thunderbird? (And for that matter, why don't those 
dictionaries come with the proper names of Firefox and Thunderbird 
pre-loaded?)

I have been using the spell-check system for many times. And I detect a 
distinct United Kingdom bias:

Words ending in "-our" instead of "-or" (colour/color, favour/favor, 
savour/savor, etc.)

The -er and -re dispute (centre/center)

The -ce and -se dispute (licence/license, defence/defense)

Meaning no disrespect to staunch defenders of the Queen's English, I 
suggest that an English-US set of dictionaries should be available. At 
least some members of this community learned (learnt?) our spelling from 
Noah Webster, not Samuel Johnson.

Temlakos