Polyglot. Learn German is a mobile guide to German Grammar. The app "Polyglot. Learn German" in a simple form will help you to learn basic German grammar. The app contains the following lessons: 1. The Present Tense. Regular verbs. 2. The Present Tense. Irregular verbs. 3. The Future Tense. Pronouns in the Dative. 4. Pronouns in the Accusative. 5. Imperative mood.