Sandbox in a 4 year web?

I have a 4 years web that some url stopped to be ranked..

4 month ago all the urls were ranking, and one day 1/3 part of the urls stopped to rank all toguether, instead of this, is ranking the home page for those keywords, but the homepage is ranking worst.

These 1/3 part of the urls are my english translation of the website, are the english spoken url,

I'm thinking to get a professional to translate these english url, maby this could solve it.

What should I do?

It could be an issue of keyword cannabalization. Yes, get someone good to rewrite those pages and make them optmized well so that they clearly target different keywords.

Thanks..

Everyone thinks is a problem of cannabslization?