Transducer is a device that will physically move or produce mechanical movement from electrical signals. Speakers are made from these in a way or another, but most of them are used to be attached to a surface in order to make that surface it self a loud speaker. To get a better idea check this video from parts-express.
Tactile means something related to the “touch sense” if i may say. Tactile transducers, then, are electrical devices that you feed them with electrical signal like Audio to produce mechanical vibration, that’s awesome. Why? keep reading.
http://www.m7md-zeid.com/tactile-transducers-what-are-they/