After spending an unusual amount of time wondering why the spellchecker of my openoffice-bin install was not working at all and greyed out in the languages config, I built app-dicts/myspell-en which got it working but this realization was hard to find after trawling the web. I 'think' the openoffice-bin ebuilds need this dependency of myspell for the required language (or hunspell which I believe replaces myspell in openoffice??). The source current version ebuild has this but the binary version does not.
*** This bug has been marked as a duplicate of bug 139512 ***