The Bible does indeed condemn false signs and "uncertain speech" that does not edify the Church.

here is an index of several articles regarding the Charismatic movement (Pentecostalism). Pentecostalism, sincere though it may be, is based on a series of false assumptions. What we practice in worship must be based upon the truth.

In that index you'll find articles not only on the gifts of the Spirit, but also on the true meaning of Holy Spirit baptism and the errors of the Pentecostal application of it.