Can it be faked? Yes, and often.
Can a true believer have sin in their lives and still manifest the Gifts or speak in tongues? Yup! Just read the litany of charges against the Corinthian Church. And yet, it says that they "came behind in no gift." I Co 1:6
Read through the letters to the Seven Churches in the Revelation. All had good points and bad points. No perfect Churches, then or now. No perfect people either. The Apostle Paul, role model for thousands; wrote 2/3 of the New Testament. Yet he considered himself to be "the chief of sinners." Yet he thanked God he spoke in tongues more than them all.
Tongues are not a shield against sin. They do however, serve to "edify" or build us up in faith, which helps us put to death the deeds of the flesh. (
Jude 20; I Co 14:4).
Keep on askin' those questions!
Matthew 7:7
Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you:
Luke 8:10
And he said, Unto you it is given to know the mysteries of the kingdom of God...
It's a grand adventure!