Use learn with a direct object when you are talking about gaining knowledge or experience of a particular skill, especially when someone is teaching you or training you. The most frequent objects are skill, technique, craft, language, and the names of languages (such as English or Chinese):
The course provides an opportunity to learn new skills.
Ireland is a popular destination for those interested in learning English.
Use learn about when you are talking about gaining more knowledge of a broad area or subject:
✗ You can just sit in front of your television and learn the culture of other countries.
✓ You can just sit in front of your television and learn about the culture of other countries.
Don’t confuse learn, study, and teach. When the process of learning implies attending classes or doing research in order to gain an understanding of an academic subject, the verb to use is study (not learn):
✗ Getting a degree in architecture involves learning higher mathematics.
✓ Getting a degree in architecture involves studying higher mathematics.
Learn is never used to mean the same as teach:
✗ University learns you how to think and judge with your own mind.
✓ University teaches you how to think and judge with your own mind.