I make forms in spanish, How do I organize languages, do I set up english as default and then add spanish as a second one?

If I set spanish as default my field in my form such as months won't be translated, What should I do?

As the Spanish language issue is only in Date (month), so I would suggest you to use  localized calendar widget . This widget is easy and quick to configure, with the options to select the language of your choice from the widget settings dialog, along with the corresponding date format.

That is, you can set the language to Spanish in it, so the date picker will be shown in Spanish language.

If you have any query, or need further assistance, feel free to revert back.

Thanks.