I just stumbled upon a very good Italian version of Diederich's Basic Vocabulary. Although this site's language is English, its visitors seem to be fairly cosmopolitan, so I thought it worthwhile to mention.
The Dizionario Frequenziale Latino (PDF, 3.6 MB, Creative Commons Licence) by Grifoni & Bucci presents Paul B. Diederich's Basic Vocabulary in 4 formats:
- Latin-Italian (alphabetically)
- Italian-Latin (alphabetically)
- By frequency
- By categories.