If you're trying to shorten it for a specific purpose, you might consider these options:
* Cult. This is short and simple, but can be misleading as it refers to a specific type of group or practice.
* Clt. This is less common but could work in some contexts.
* Cultural aspects could be abbreviated to CA.
* Cultural exchange could be abbreviated to CE.
Ultimately, the best abbreviation depends on the specific context and what you're trying to convey.