General synonyms:
* Acquire
* Absorb
* Comprehend
* Grasp
* Master
* Pick up
* Study
* Understand
*
More specific synonyms:
* Discover: To find out something new or unexpected.
* Educate: To teach or train someone.
* Memorize: To learn something by heart.
* Practice: To do something repeatedly in order to improve.
* Research: To investigate a subject systematically.
* Study: To devote time to learning about a subject.
Informal synonyms:
* Get the hang of: To understand how to do something.
* Figure out: To discover or understand something.
* Pick up: To learn something quickly and easily.
* Catch on: To understand something.
The best word to use will depend on the specific situation and what you are trying to convey.