in what application are you going to use this function?
the first that comes to my mind is to put together 3 inverted amplifier for each part of the function. Then you need 2 comparators, analog muxer with at least 3 inputs and would need a voltage supply that exceeds ±15V - and some logic gates between so it can choose the appropriate function.
That will be a mess - espechially if it's supposed to be little faster than slow.
For this latter case, check papers on Emitter Coupled Circuits (ECC) or Gilbert Cell, e.g. this one (search for tanh): View attachment analog_multipliers.pdf