The spell checker in Firefox 2 is certainly a great feature. I have already seen lots of people write this and I agree. And yet, it has some certain deficiencies that make me use it far less than it could be. The reason is: it seems to assume that you always write your texts in the same language. Yet I am frequently switching between languages, I write texts in English, German and Russian all the time. And going to the context menu, digging into the languages menu and choosing the right language is just annoying, especially for a short text. There is also another issue: switching languages takes a while, and for a huge dictionary like the German (10 MB) it becomes a major annoyance.
These issues could be solved of course. For example one could make the UI for switching languages more accessible by adding keyboard shortcuts, maybe Ctrl+Shift+1 through Ctrl+Shift+9 (extension, somebody?). Then, when I switch away from a language this probably doesn’t mean that the dictionary should be released — I want it to be kept in memory. I don’t care about the extra 30 MB of memory usage for the German dictionary but I care very much about the 10 seconds delay when Firefox has to load it again.
There is one more problem due to a “feature” in the Russian language. Russian has something that can be called “half a letter” — “ё”. This letter represents a certain sound but it never managed to get really accepted, it is allowed to substitute it by a regular “е”. Consequently there are two Russian dictionaries, one that enforces the use of “ё” and one that required you to substitute “ё” by “е”. Now I am used to the common practice of writing out “ё” in the ambiguous cases only like “все” vs. “всё” — that’s two absolutely different words. However, I cannot do this with either of the two dictionaries. So what I would like to have is the spell checker treating “ё” as an ambiguous letter and accepting both “ё” and “е” for it. I don’t know, are there other languages that have the same problem?