Well, i see this file .../Scripts/Language.py and seems that only it needs to change the parameter to Current = "English"... and rename the folders called "Spanish" to "English". Good, it is more easy than i thought.
Remains to translate all the texts and images... a lot of work, but it is nothing to me.
My english is not well, so the translate may be not perfect. Sorry.
When i need help with a large text, i will put it in here, if somebody could help a little would be great.