This is the largest list of dictionaries on one page . . over 180 the last I counted, and I stopped counting months ago.
http://libreoffice-na.us/English-3.5-installs/dictionary.html#english
The ones that start with "kpp" are the ones I created.
Download the .oxt file[s] you want and use the Extension Manager to install it. The largest American dictionary/thesaurus has over 773,000 words in it.
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As for Calligra - the web site talks about it being part of the "KDE community"
But it might now be as easy as you like to get it, according to the way I read the text below.
"Therefore you can download and install Calligra Suite in most cases free of charge. While the Calligra project only provides source code, it is easily installable through the package manager of many linux distributions, FreeBSD. There is also preliminary support on Mac OS X and Windows."
I wonder how much of it is based on the old OOo coding.