Practice

The Strengthen skills (or practice) button provides a number of  exercises reviewing material learned in lessons, with a focus on the material that Duolingo believes the user most needs practice in at that moment. Such practices are untimed by default; however, a timed practice option is also available for purchase in the Lingot store. Untimed tests always earn the user a minimum of 3XP, and a maximum of 10XP.

How it works

Prompt to choose between timed and untimed practice

A practice session may result in strengthening the words practiced, and if enough words from the same skill are strengthened, also strengthening one or more related skills. So "it is very possible that practicing one skill can strengthen another skill". A session doesn't necessarily need to be completed successfully in order to strengthen skills, especially if one uses a timed practice . However, it may take more than one try to fully strengthen a skill (e.g. make it gold). 

Best practices

According to Duolingo, "learners should first focus on finishing all the lessons in a skill, and later come back to review them at just the right times".

Purpose

Strengthen skills helps users to:

• Memorize;
• Test their knowledge;
• Review learnt material; and 
• Maintain and improve their skills.

Notes

Global strengthen skills shows a message and doesn't allow more practice when :

Algorithm thinks your words are all fresh.

See also

• Discussion about word strength
• Frequently asked questions/Practicing