I am having a problem in the display of the hours

[RR28]

when displaying the weekview the hours are displying is this in form (9 de manha -> means 9 am .. 1 da tarde -> means 1 pm)

but i much prefer the normal way (9:00 - 10:00 .. 13:00 .. 16:00)

i have the feeling that it used to display the way i prefer before (thats how i got the print) but now its stuck in the am/pm form can someone explain why this happened and what i need to to do to change