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Why can't I speak in tongue

The holy spirit

Acts 1 v 8A
but yeah shall receive power after that the holy spirit is come upon you:

Who is the holy spirit?

God is the spirit, he is holy, the Godhead (holy Trinity) is made up of three persons ; the father, the son, and the holy spirit.
Many people believe he is a servant to God, this is false, actually the holy spirit is equal to in no way inferior to God nor his son Jesus Christ, He is the God that is present today on earth.

The holy spirit is the greatest personality on earth and the greatest gift God gave to his children, in him we have our being and life.

Why don't I speak in tongues?

The reason is simple, it because you have not really opened your heart to receive the holy spirit, it takes a holy invitation for the holy spirit to dwell in any believer, and also the perceived willingness to obey him, before he can come into your life.

Am I still born again even if I don't speak in tongue?

Yes you are a born again, even if you don't speak in tongue, the holy spirit is in every believer, to guard you through all difficulty and all truth,
Once you have that still voice that whispers to your heart the right thing to DO, IT means you have him.
Ok
Let me digress, the fact that you dont speak in tongue, does not mean you will go to hell fire, or you are a sinner, and that does not also mean you don't have to pray to receive it

For the speaking of tongue is a clear sign that you are christ-like, speaking in tongue is the evidence the world needs to attest to your faith in Christ. That is why we all need him.

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Remember, he is a gift from God, which can be prophesy, deliverance, healing powers etc.
So it is not a sin if you don't have any of those powers, but it is wise to admire to have one
So as we go to church this morning, it a duty call for us to receive the holy spirit in the dimension that he wish for us through the father.
It can be prophecy, interpretation of tongue, healing, deliverance, supplication for others, etc.