Castilian dialect, Spanish Castellano, a dialect of the Spanish language (q.v.), the basis of modern standard Spanish. Originally the local dialect of Cantabria in north central Spain, Castilian spread to Castile. After the merger of the kingdoms of Castile, Leon, and Aragon in the late 15th century, it became the standard language of all Spain and in the following centuries the language also of Spanish America.
The model you gave is a little unclear, but I think it would be:
1) Ricardo voy a preparar su tarea a las ocho y cuarto.
2) Isabel y Ricardo van a cenar a las nueve.
3) Isabel voy a ver la television a las nueve y treinta y cinco.
4) Ricardo voy a caminar con el perro a las diez menos cuarto.
Answer:
El martes, 2 de enero de 2018.
