WCF XMLAttribute

I am returning some XML from WCF... using DataContract and DataMember

[DataContract]
public class Code
{
    [DataMember]
    String NuclearLaunchCode;

    [DataMember]
    String MessageToEnemy;
}

which will output

<Code>
   <NuclearLaunchCode>34526</NuclearLaunchCode>
   <MessageToEnemy>Have a Nice Day</MessageToEnemy>
</Code>

However I would like to have an attribute in the code Tag and the Nuclear tag

<Code PresidentOnly='true' >
   <NuclearLaunchCode>34526</NuclearLaunchCode>
   <MessageToEnemy language='Gaelic'>Have a Nice Day</MessageToEnemy>
</Code>

How do I modify My DataContract to output an Attribute?

I Tried adding

 [XmlAttribute("language")]
String language;

But it didn't work .. any ideas?