Just so you know, Trump speaks to the working class in general, and speaks like they do. They aren't copying him, it's the opposite.
Here in America, Trump speaks to the working class by speaking the way they do instead of speaking down to them.
To be honest it's refreshing: the working class is a huge portion of the population here - like it or not - and unlike others who look down their nose at people, they worry more about putting food on their families table than they do appearance's and perfect manners.
Most people are just people, and a good portion of the nation speaks just like Trump. They just say what they think when among friends, and that's how Trump speaks to them.
It's how he connects with his base, first billionaire in history to become one of the regular folks - someone you might enjoy a beer with.
As far as is it Christian to speak with people in the language and manner they use - it's just positive communication instead of negative, neither Christian nor unchristian..