Skills are organized into a language tree. These skills are named after the part(s) of speech, grammar or subject that the skill covers. Every language tree begins with Basics skills that provide the vocabulary to begin constructing simple sentences and to start learning a language.
Skill advancement is shown in three different ways.
Beginning May 2019 on the web, percentages are used. If you finished 5 lessons out of 10 or 15 lessons out of 30 you will see "50% Complete".
In iOS the next lesson is shown. If you finished 5 lessons out of 10 you will see "Lesson 6/10".
In Android, and previously on the web, the last lesson is shown. If you finished 5 lessons out of 10 you will see "Lesson 5/10".
Skill strength and decayEdit
Each skill has a strength associated with it. When a skill is first learned -- either by completing the lessons or passing a test -- it is at full strength. Over time, if not practiced, it decays. Practicing the skill will raise its strength back up. With the introduction of the Crown system, this strength is no longer visible, but it will affect which skill is chosen with the Strengthen skills button
There are several ways to increase the strength of a skill:
- Strengthen skills - Practicing using the "strengthen skills" button;
- Redo skill/lesson - Redoing old lessons/skills.
Skill decay occurs when learners don't practice the words in a skill. The rate of decay depends on factors such as how much the words have been practiced and how well the user did when practicing them.
Types of skillsEdit
There are several types of skills used to teach concepts to language learners and some teach the core grammar while others teach subject specific skills. These skills cover topics such as:
- Grammar - This is taught throughout the tree and may include lessons on parts of speech, tenses and moods, grammatical particles, cases, or other topics depending on the specifics of the particular language's grammar.
- Subject-specific vocabulary - Duolingo covers many subjects within the tree such as sports, clothing, and food.
- Bonus Skill - These come in various forms and teach things such as idioms or holiday vocabulary.