Which psychologist soon disproved wundt's argument that learning and memory could not be studied experimentally?

I believe the answer is: Ebbinghaus

For his experiment on memory, Ebbinghaus use simple acoustic encoding and maintenance rehearsal that make a subject try to remember several list of words that have similar syllabels and ending.

As it turned out, language and memory shows strong correlation because people are much more likely to forget or mixed up the meaning of similar sounding words.