I also wondered about how to use "tease", and that was "saying" should be inserted between teased her (saying) that if
, but this doesn't need it. So don't you have to say "saying" to denote a delivered message when you use "tease'?

ex)...Lisa caught on to the hand signs they used to order food and drinks, but they often teased her that if she was seriously interested in her customers, she should learn to communicate in their language...