  # String types...
  
  class CharField(Field):
      default_error_messages = {
          'blank': _('This field may not be blank.'),
          'max_length': _('Ensure this field has no more than {max_length} characters.'),
          'min_length': _('Ensure this field has at least {min_length} characters.')
      }
      initial = ''
      coerce_blank_to_null = False
      default_empty_html = ''
  
 
</s> remove         'max_length': _('Ensure this field has no more than {max_length} characters.'),
 </s> add         'max_length': _("Ensure this field has no more than {max_length} characters."), </s> remove         'max_length': _('Ensure this filename has at most {max_length} characters (it has {length}).'),
 </s> add         'max_length': _("Ensure this filename has at most {max_length} characters (it has {length})."), </s> remove         'required': _('This field is required.'),
        'null': _('This field may not be null.')
 </s> add         'required': _("This field is required."),
        'null': _("This field may not be null.") </s> remove         'invalid': _('A valid number is required.'),
        'max_value': _('Ensure this value is less than or equal to {max_value}.'),
        'min_value': _('Ensure this value is greater than or equal to {min_value}.'),
        'max_digits': _('Ensure that there are no more than {max_digits} digits in total.'),
        'max_decimal_places': _('Ensure that there are no more than {max_decimal_places} decimal places.'),
        'max_whole_digits': _('Ensure that there are no more than {max_whole_digits} digits before the decimal point.'),
        'max_string_length': _('String value too large.')
 </s> add         'invalid': _("A valid number is required."),
        'max_value': _("Ensure this value is less than or equal to {max_value}."),
        'min_value': _("Ensure this value is greater than or equal to {min_value}."),
        'max_digits': _("Ensure that there are no more than {max_digits} digits in total."),
        'max_decimal_places': _("Ensure that there are no more than {max_decimal_places} decimal places."),
        'max_whole_digits': _("Ensure that there are no more than {max_whole_digits} digits before the decimal point."),
        'max_string_length': _("String value too large.") </s> remove         'invalid': _('A valid integer is required.'),
        'max_value': _('Ensure this value is less than or equal to {max_value}.'),
        'min_value': _('Ensure this value is greater than or equal to {min_value}.'),
        'max_string_length': _('String value too large.')
 </s> add         'invalid': _("A valid integer is required."),
        'max_value': _("Ensure this value is less than or equal to {max_value}."),
        'min_value': _("Ensure this value is greater than or equal to {min_value}."),
        'max_string_length': _("String value too large.")
        'blank': _("This field may not be blank."),
        'max_length': _("Ensure this field has no more than {max_length} characters."),
        'min_length': _("Ensure this field has at least {min_length} characters.")
  # String types...
  
  class CharField(Field):
      default_error_messages = {
        'blank': _("This field may not be blank."),
        'max_length': _("Ensure this field has no more than {max_length} characters."),
        'min_length': _("Ensure this field has at least {min_length} characters.")
        'blank': _("This field may not be blank."),
        'max_length': _("Ensure this field has no more than {max_length} characters."),
        'min_length': _("Ensure this field has at least {min_length} characters.")
        'blank': _("This field may not be blank."),
        'max_length': _("Ensure this field has no more than {max_length} characters."),
        'min_length': _("Ensure this field has at least {min_length} characters.")
      }
      initial = ''
      coerce_blank_to_null = False
      default_empty_html = ''
  
keep keep keep keep replace replace replace keep keep keep keep keep
 use double quotes for user visible strings; end user visible strings in full stops; add some missing translation tags 
rest_framework/fields.py