Change Capitalized Text to Title Case With Regular Expression

For Spanish, this should do the trick:

Substitute \b([A-ZÁÉÍÓÚÑ])([A-ZÁÉÍÓÚÑ][\wÁÉÍÓÚÑ]*) with \u$1\L$2.

To capitalize back roman numerals, acronyms or initials, make a list: ([IVXL]{2,}|CONACULTA|FONCA|INAH)and substitute with caps: \U$1 (you might need to set your respective editor to Match or Preserve Case).