Verilog and VHDL are description languages for hardware which are used in writing programs for electronic chips. Verilog is more recent than VHDL. Verilog deals with C, while VHDL is based on Ada and Pascal. VHDL language is typed strongly, but Verilog is a weakly typed language. Also, Verilog is case sensitive, but the VHDL is not case sensitive. In Verilog, if the letter case is not consistent, it will not recognize the inputted variables, but the VHDL can still recognize it so far the characters in the order and in the name remain the same.
VHDL is the more complex of the two, but it is easier to learn Verilog simply because the C programming language is popular. Verilog makes use of data types that are simple, but the VHDL gives a chance to create data types that are more complex and complicated. Just like Verilog also, VHDL lacks software programming languages' library management.