Problem with translation

On my page:
www.mojhrt.si/component/users/?view=registration

When I just click register or registracija without entering any data, I get error messages in english: This is a required field.

Where do I change this to my language? I searched everywhere but can't find the location of this text.

Thank you

Which browser? Can you take a screenshot?

Hi,
can't you just click the link I gave and click registracija button? You'll see it for yourself???

I don't, that's why I asked for browser information and the screenshot.

That happens to me too only I cant even get the recaptcha to work every time it says the captch fails. Joomla 3.4.1 Ajax Reg 3.4.2 Firefox 36 Chrome 41, Explorer 11... And does it use the New recaptcha v2?
I got new codes from Google but nothing...