What is Speaker?
It looks like it is an interface or an abstract class.
If it is, you cannot instantiate it. You should instantiate a class extending Speaker or an implementation of Speaker interface instead.
A hint: your method would be better if it declared it returns List<Speaker> instead of ArrayList<Speaker>.
If you even feel a need to use different implementation of list, you would be free to do so without braking or changing your (or other people's) code.
You cannot create an object of "Speaker". Is it an interface? Is it an abstract class? Is the class's constructor private? Does it require use of a singleton to get ahold of? Does it consist of only static use methods?
"For an idea that does not first seem insane, there is no hope." - Albert Einstein