You can get the setup package of 不規則動詞 1.4.1.108 for free and take a look at users' reviews on Droid Informer. The app runs on Android 2.3.3 and above. The download of this application is 100% safe. Euvit, s.r.o. is the developer of the tool which can be found in the Educational category.
The developer rolled out a new version of 不規則動詞 on Jul 9, 2015 and over 5 users downloaded and installed the app. The average score for this application is 4.1 on Google Play.