My page turned to English on3.8.1 update

Hello, i just realize of a big issue on my page.

As background, my web page was in spanish language, actually i had translated the whole page using the language _ES and it was working wonderfully.

After upgrading to 3.8.0 from 3.8.1 i noticed that now in my dashboard (in the bottom of the left column) i have 2 language selection menus, one for Spanish and another for English.

Actually if i want to write a new post i have to option to input both tittles and text in both languages.

My readers are reporting having issues visualizing my web page due to this issue.

How can i bring back my web page to ONLY SPANISH language and not multilanguage?

All of the text elements of my theme have turned to english… login access, post info on comments, date of publishing, and all of the other text elements…

Thanks a lot for your support.