Solved by J_Johnson in post #2 
              
              
                Okay, figured it out. I changed 
counter.update(tokenizer(string_)) 
to: 
for elem in list(tokenizer([string_])):
    counter.update(elem)

And also: 
en_vocab=build_vocab('sample.csv', vocab_tokenizer) 
to: 
en_vocab=build_vocab('sample.csv', sp_tokens_generator) 
That allowed me to then save the v…