General:
* Deal with
* Tackle
* Handle
* Resolve
* Attend to
* Focus on
* Consider
* Discuss
* Examine
* Explore
For specific situations:
* Speak to (a person or issue)
* Respond to (a question, criticism, etc.)
* Correct (a mistake)
* Improve (a problem)
* Eliminate (a concern)
* Treat (an illness)
* Contact (a person or organization)
* Locate (a place)
* Direct (a letter)
More formal:
* Confront
* Engage with
* Investigate
* Analyze
More informal:
* Get to
* Sort out
* Take care of
* Fix
The best alternative will depend on the specific context. For example, "deal with" is a good general alternative, while "speak to" is more specific to addressing a person or issue.