Mark 16:17- And these signs shall follow them that believe...THEY SHALL SPEAK WITH NEW TONGUES.
Speaking in unknown tongues is one of the signs that must be evident in the life of a believer, Jesus didn't make mistake to have said that. When we call something a sign, we're talking about a mark of identification.
Some may ask If it is a must for believers to be baptized with the evidence of speaking in tongues? The answer is YES because JESUS said so in Mark 16:17 that it is one of the ways to identify a believer. Don't let the devil cheat you of this wonderful experience.
You may have prayed, fast or get hands laid on you to receieve the baptism of the Holyghost, If you don't receive it by faith, you may wait for decades. When next you pray, simply voice out the words the Spirit of God is laying in your spirit.
Father, I receive fresh baptism of the HolyGhost In Jesus Name.