Having four different tables or having one table with one more field?
Having all languages in one table is an overhead. Each time you will have to load the data of all languages and use part of (for one language), or you will add a condition to your query to load one language's data, which is also an overhead. In my opinion, having each language is a separate table is lighter. However, if the load on your website is low, and your translation data is not big, the difference will be negligible.