Exclude attribute name prepending in error message

Question

I have a simple internationalization:

attributes:
  user:
    login: Login
errors:
  template:
    header: "Errors"
    body: ""
  models:
    user:
      attributes:
       login:
         taken: "The chosen {{attribute}} is already registered"

The resulting error message is as follows:

Login The chosen Login is already registered

It seems, like Rails automatically prepends the error messsage with attribute name. This forces me to arrange messages in only one way - with attribute name as a first word.

I need the following error message:

The chosen Login is already registered

How can I configure Rails to not prepend the error message with the attribute name?