Answer:
They expanded the definition of the right to free speech beyond the spoken word
Step-by-step explanation:
"Tinker v. Des Moines case" was all about the black armbands that a group of students wore as a form of expression in protesting against the war that was happening in Vietnam. They were suspended and this sparked a debate regarding the "freedom of speech" enclosed in the Constitution.
As a result, the right to free speech was properly addressed by the Supreme Court as something that will allow the students to express themselves without affecting the policy of the school.
So, this explains the answer.