The two-language problem refers to prototyping with one slow dynamic language and rewrite it with a fast static language for the final product.
If Julia really solves the two-language problem, it should meet the following criteria: Let A be the code written during prototyping, B be the code written for the final product, with a small net increment $\Delta$, A+\Delta=B. If Julia uses one code style to do prototyping, and then uses a completely different style to write final product, then it can't be called the same language. At best, Julia turns the 2-language problem to a 1.5-language problem.
