
Given the following passage

"Catalan is split in two major dialectal blocks: Eastern Catalan, and Western Catalan. The main difference lies in the treatment of unstressed a and e; which have merged to /ə/ in Eastern dialects, but which remain distinct as /a/ and /e/ in Western dialects. There are a few other differences in pronunciation, verbal morphology, and vocabulary.",

answer the following question. Note that the answer is present within the text.

Question: How do these differences compared? 

The main difference lies in the treatment of unstressed a and e; which have merged to /ə/ in Eastern dialects, but which remain distinct as /a/ and /e/ in Western dialects
