Ahh, there's the rub. Plenty of disagreement as to WHEN they will cease to be needed. "When the perfect comes"
What is this "perfect" ??
Some say the canon of scripture, some say Christ. Could be our resurrected body, whereby we will be perfect and complete
So your question assumes you know the answer ??
No, the gift of tongues is already dropped from verse 9-10 in regard to "that" which is perfect. The only two considered is "knowledge" and "prophecy."
Paul uses the passive voice in verse 8 for knowledge and prophecy indicating that something must stop them. However, tongues are referred to in the middle voice - stop of themselves, thus not needing anything to stop it. Thus it is dropped from consideration in verse 9-12.
Furthermore, verses 10-12 provide three axioms (self-evident truths) in the form of principles that provide a progression in thought, but basically say the same thing.
• Verse 10 - what is in part remains in part until that which completes it arrives.
• Verse 11 - what is immature remains immature until that which matures it arrives.
• Verse 12 - obscure indirect revelation remains obscure until it is replaced by direct clear revelation.
However, “now” in lieu of no clear direct written revelation concerning the proper use of spiritual gifts in the assembly, love provides a mature principle to guide them in this matter. Love is complete and is greater than faith or hope because it is inclusive of both (“believeth all things” “hopeth all things”). Hence, love provides a mature principle to define the proper use of spiritual gifts “now” (14:1) until “in part” revelatory gifts are done away by a more direct completed revelation – the finished word of God.
One must ask why did Paul choose tongues, knowledge and prophecy only in verse 8? Because these are representative of sign and revelatory gifts used to convey the revealed will of God. However, not all believers had these gifts, and thus much of the members could only see "darkly" and had to depend upon those members with these gifts, who also only possessed "in part" revelations and saw "darkly" as well. However, when that which completes revelatory gifts arrives - the completed Biblical canon as prophesied of in Isaiah 8:16-20; John 14-17; 2 Pet. 3:15-17; Rev. 1:3; 22:18-19 then there will be clear revelation about church policy directly to each saint without depending upon indirect incomplete revelatory gifted individuals. These gifted individuals also had to be tested to confirm what they said was from God (1 Jn. 4:1; 1 Cor. 14:29) which also made this "in part" method more "darkly" than simply opening up God's completed written revelation and reading directly His revealed will in any given matter.
The epistle of 1 Corinthians by Paul was part of completing that process - 1 Cor. 14:36-38