VHDL-AMS
VHDL-AMS is a simulation language for simulation of mixed signal systems (not only electrical systems but also thermal, hydraulic, .....), I used a mentor graphic product called System Vision but it was not that so good. But if you want a start tutorial try to find the tutorials that come with System Vision it will clear a lot about this language and how to use it.
Of course this language can not be used to implement anything on a FPGA (as it is not dedicated for digital systems only)