Can we assign / change traits to the scala class during runtime? How - any sample code? Like Strategy Pattern (of Gang of four Design Pattern)

Question

To explain my question:

Class : Toy

Trait1: Speak like Male

Trait2: Speak like Female

Can I change the behavior (traits) of Toy during runtime so

Answer 1

sealed trait Speaker
case object Male extends Speaker
case object Female extends Speaker

class Toy(name: String, speaks: Speaker = Male) { 
  def speak = speaks match {
    case Male   => "ugh"
    case Female => "What time do you call this?"
  }
}

Then

barbie = ken.copy(speaks = Female)

You cannot change the traits which an object extends at runtime, because a trait is mixed in to create a class (in a .class file). A given object has exactly one class and this can never be changed.