User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.9) Gecko/20071025 Firefox/2.0.0.9 Build Identifier: 1.0.5.13 This would be a "cool" feature...maybe? With so much of the net getting connected, I find I have messages using words from other languages...most often are British spellings, though even French idioms are nearly "de rigueur" at times with Latin (et cetera, et alia) being less common. But the functionality would be to *underline* the words (as though they are mispellings), but in a different color. To not slow things down "excessively", I'd go for the initial spellcheck in the primary language -- then check a user's alternate dictionary list, _in background_ (while waiting for user input). When a word is found in an alternate dictionary, if the "misspelled" is still on the screen (and presumably, still underlined), the underline would change to an "alternate" color. This could indicate that while the word is misspelled in the primary language, it is not misspelled in some secondary. A right-click would show on the menu above the space currently used for alternate "suggestions" "(found in <dictionary-name>)". So if I was using "English (US)" as my primary, and had "English (UK)" and used the word "theatre", it would show "(found in English (UK))", followed by the list of US-English replacement suggestions ("theater"). Reproducible: Always Steps to Reproduce: 1. Assume English(US) as primary spell dictionary 2. Load English(GB) as another dictionary. 3. type "theatre". Actual Results: word is underlined, in red, as "misspelled" Expected Results: Same. (since this is an RFE.) :-) Though -- might be nice if word was underlined in "orange"? "yellow"? (caution)? right click would show word as "found in English(UK)", then go on to "normal output": English(US) alternate spellings (theater), etc.

Related to/duplicate of Core bug 69687 comment 32?

To me, this sounds like an very complicated design for what should be a simple, easy-to-use feature.

Related to bug 355329.