ArabiCorpus (Research)

ArabiCorpus is a free, untagged, 30-million-word corpus with a user-friendly interface. Maintained by Dil Parkinson, professor of Arabic, this corpus allows users to find larger structures and grammatical patterns through frequency analysis, regular expression searching, and other advanced interface features.

The ArabiCorpus is a highly regarded tool for both researchers and advanced Arabic students, and can be found at http://arabicorpus.byu.edu.