How to change the default error message on forms - 7.1 from spanish to english.

I'm trying to change the language of the error messages from spanish to english. 

I tried using this link "https://www.silvabokis.com/squarespace-tips-archive/dynamic-translation-of-squarespace-form-error-messages" with no success. 

I don't know if for the spanish version the default messages have a specific string so I can address those ones and change them.

I tried with this:

var errorSP = {
    "El campo 'Full Name' es obligatorio.",
    "El campo 'Email' es obligatorio.",
    "Falló el envío del formulario. Revisa la siguiente información: Full Name y Email.",
    "Falló el envío del formulario. Revisa la siguiente información: Email.",
    "Falló el envío del formulario. Revisa la siguiente información: Full Name.",
    "Email no es válido. Las direcciones de correo electrónico deben seguir el formato usuario@dominio.com."
};

// Translations
var errorEN_Translated = {
    "The 'Full Name' field is required.",
    "The 'Email' field is required.",
    "Form submission failed. Please check the following information: Full Name and Email.",
    "Form submission failed. Please check the following information: Email.",
    "Form submission failed. Please check the following information: Full Name.",
    "Email is not valid. Email addresses must be in the format user@domain.com."
};

Can you share link to page where you use form?