i am playing a bit with some code snippets and i am asking if its possible to use a function that was defined in a child class (with extends), to use in a variable that was created with the parent class?

Here is my code snippet:

class Workshop {
constructor(teacher) {
    this.teacher = teacher;
}
ask(question) {
    console.log(this.teacher, question);
}
}

class AnotherWorkshop extends Workshop {
    speakUp(msg) {
        console.log(msg);
    }
}

var shallowJS = new Workshop("Toby");

shallowJS.ask("you are there?");
shallowJS.speakUp("still there?");

Is there anyway, that i can access the function speakUp from the child class AnotherWorkshop with shallowJS.xxxx ? (and i dont mean the way to create a new variable of shallowJS)

Thanks a lot for help :)