The only Biblical purpose was to VALIDATE the NEW TESTAMENT was as Much the Word of GOD to the Unbelieving JEWS to fulfill Prophecy, just like the Old Testament Prophets that also did Miracles of GOD to validate it came from GOD.
1 Corinthians 14:21-22 (ESV)
21 In the Law it is written,
“By people of strange tongues and by the lips of foreigners will I speak to this people {the Jews}, and even then they will not listen to me, says the Lord.”
22
Thus tongues are a sign not for believers but for unbelievers {the Jews},
while prophecy is a sign not for unbelievers but for believers.
Isaiah 28:11-12 (ESV)
11
For by people of strange lips and with a foreign tongue the LORD will speak to this people {the Jews},
12 to whom he has said, “This is rest; give rest to the weary; and this is repose”; yet they would not hear.
1 Corinthians 1:22 (KJV)
22
For the Jews require a sign, and the Greeks seek after wisdom:
1 Corinthians 14:33-35 (ESV)
33 For God is not a God of confusion but of peace. As in all the churches of the saints,
34
the women should keep silent in the churches.
For they are not permitted to speak, but should be in submission, as the Law also says.
35 If there is anything they desire to learn, let them ask their husbands at home.
For it is shameful for a woman to speak in church.
Mark 16:20 (NIV)
20 Then the disciples went out and preached everywhere, and the Lord worked with them and confirmed his word by the signs that accompanied it.
When the New Testament was confirmed to enough witnesses, I believe the purpose Ceased, and so did the genuine TONGUES Cease. All that remains is nothing more than a counterfeit of the Real McCoy. Just like Jesus does not continue to validate HIS RESURRECTION to every new believer by appearing to him.
Acts 2:5-11 (HCSB)
5 There were Jews living in Jerusalem, devout men from every nation under heaven.
6 When this sound occurred, a crowd came together and was confused because each one heard them speaking in his own language.
7 And they were astounded and amazed, saying,
“Look, aren’t all these who are speaking Galileans? {Galileans were know to have a strong accent, like someone in the deep south of the USA, or an Irishman.}
8
How is it that each of us can hear in our own native language? {dialektos is so specific of a language that EVEN the accent was 100% correct.}
9 Parthians, Medes, Elamites; those who live in Mesopotamia, in Judea and Cappadocia, Pontus and Asia,
10 Phrygia and Pamphylia, Egypt and the parts of Libya near Cyrene; visitors from Rome, both Jews and proselytes,
11 Cretans and Arabs—
we hear them speaking the magnificent acts of God in our own languages.”
{All JEWS had to learn and memorize the MAGNIFICENT ACTS OF GOD specifically, so it was a LANGUAGE, not Jibberish.}