Hi Katia,
I am not sure I understand your question, but here it goes:
You can change the default language written by Etsy by clicking on "You" on the top right corner. Then click on "Account Settings" and select the "Preferences" tab. Select the language of your preference. Do not forget to click on the "Update Preferences" button at the bottom of that page, otherwise you will lose your preferences.
This will change everything to Spanish, except the text inserted by you in your listings (Titles, descriptions, etc., etc.). You will have to do that yourself.
I hope this helps.