It is my opinion that the signs mentioned in
Mark 16
exorcism or casting out devils
speaking with new tongues/languages
taking up serpents (protection)
protection from the results of drinking poison
healing the sick by the laying on of hands
refer to signs that follow or accompany the body of believers collectively.
In other words, over the course of history these signs have been seen among God's people.
It is my opinion that not all of these signs must follow each individual believer.
Didn't the Apostle Paul ask the question, "do all speak with tongues?"in a manner and in a context that expected an answer of "no"?