I am surprised at the irrationality of this system.

They are using English as a common language.

Please leave a message on the message board.

I am studying natural language processing at university.

Natural language processing is the technology that allows computers to understand and generate human language.

Creating a new recipe is a series of trial and error.

He repeated trial and error to create a new recipe.

He ignored my opinion by coercion.

He has a stubborn personality and rarely changes his mind once he has made a decision.

His stubbornness sometimes causes problems.