Faster method for loading a hash table
An ultimate speedup is achieved by preprocessing the dictionary one step further, into the binary format. Group the words of the same hashcode together, and prepare a TOC as an array of file offsets of each such group at the beginning of the file. This way the dictionary loads in a single fread() (you may also want to account for endianness with bit more sophisticated format).

I also found strange that you add nodes at the end of the list. Unless you have a very strong reason of doing so, crawling lists is a pure waste of time. Inserting node at the head unconditionally may - or may not - gain some performance, depending of the quality of the hash.

That said, I may only reiterate on the @Edward comment: profile the code.