In what way do you want to configure this dictionary setting?

Doesn't it work if you set this dictionary once via the right-click context menu in a text area?

If you do not keep changes after a restart or otherwise have problems with preferences, see:

• http://kb.mozillazine.org/Preferences_not_saved

Currently every time start typing content in a new page, or tab textbox, browser defaults to undesired language, causing every text to be underlined with red squiggly line -very frustrating.

It actually a very common problem if you search online.

I think, though I really do not know for certain, that the problem stems from more than one language being chosen in Firefox 28.0 Tools > Options > Content > Languages. Its currently configured in the following order; "English/United States [en-us]", "English [en]", and "Spanish [es]".

It continues to default to Spanish when English has been "Moved Up" to first position.

This can happen if you visit a web page that sets "es" as the preferred language.

• bug 338427 - Spellchecker should respect @lang

Please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html

That was not the was.

In one page there was no lang defined, the other it was English. Both cases it always defaults to Spanish.

Does the value of the spellchecker.dictionary pref change?

Are you using an English Firefox version or a Spanish Firefox version?

Are there default dictionaries installed in the dictionaries folder in the Firefox program folder or did you install dictionaries manually as extensions?

Q. Does the value of the spellchecker.dictionary pref change? A. Don't understand, please elaborate.

Q. Are you using an English Firefox version or a Spanish Firefox version? A. English.

Q. Are there default dictionaries installed in the dictionaries folder in the Firefox program folder or did you install dictionaries manually as extensions? A. Extension.

I don't know if this can help you, but; I once had problems with my spell checker. After a VERY long time, I discovered that one of my add-ons was causing the trouble.

You mentioned the spellchecker.dictionary pref in the first post.

Does this pref keeps its value when this change happens?

You can open the about:config page via the location bar.

• http://kb.mozillazine.org/about:config

The problem is, that there is no "default" spellchecker.dictionary configuration option that I am aware of.

Firefox 28.0; Tools > Options > Content > Languages. Its currently configured in the following order; "English/United States [en-us]", "English [en]", and "Spanish [es]". But I don't believe this option has anything to do with spellchecker.dictionary.

According to Mozilla Firefox support:

 https://support.mozilla.org/en-US/kb/settings-fonts-languages-pop-ups-javascript?redirectlocale=en-US&as=u&redirectslug=Options+window+-+Content+panel&utm_source=inproduct#w_languages    (neater locale agnostic link to follow ~J99 -> )

Settings for web content, pop-ups, fonts, and languages_language This option is to chose which language one wishes to display information in the page is available in multiple languages.