It's not harder, it just requires different type of fitness. For example, there is a very good and highly effective, although intensive, way to learn to speak D

It's not harder, it just requires different type of fitness. For example, there is a very good and highly effective, although intensive, way to learn to speak Dutch - Delftse Methode. There they focus on building speaking skills by, surprise-surprise, a lot of speaking, training and remembering standard situations. I think, there may be similar methods for other languages.