Pentecostals do not teach that you must be baptized in the Holy Ghost with the evidence of speaking in tongues to be a "real believer". There may be a minority group out there, an ignorant extremist, who might say such a thing. but they do not express the views of most Pentecostals. The examples in Acts are of believers who are already born again receiving this gift. The largest Pentecostal group Assemblies of God (70 million worldwide) have published doctrinal papers on this subject and they are worth reading. They make it clear that they believe a person is born again by faith in Jesus Christ and that the Holy Spirit comes to dwell in the believer at that time and that person is saved or a "real believer". This is not the same as the Baptism of the Holy Spirit to receive power to be a witness. When people make the accusation that Pentecostals teach that you have to speak in tongues to be saved I often wonder if they actually heard someone make such a stupid statement or if they are just making that accusation up on the fly in an attempt to get people to agree with their views. As if they are hoping people will believe that Pentecostals teach that, when they know they do not. Like the Judaizers accusing Paul of teaching something extreme that they knew he did not teach but spreading the lies anyway just to turn people away from hearing anything he preached.
Now you may have heard that speaking in tongues is the biblical evidence that one was baptized in the Holy Ghost. I challenge you to search the scriptures in Acts and come up with better scriptural evidence. The following passage from Acts tells us that speaking in tongues was how Peter knew they had received the baptism of the Holy Ghost.
44While Peter yet spake these words, the Holy Ghost fell on all them which heard the word.
45And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Ghost.
46For they heard them speak with tongues, and magnify God. Then answered Peter,
47Can any man forbid water, that these should not be baptized, which have received the Holy Ghost as well as we?
48And he commanded them to be baptized in the name of the Lord. Then prayed they him to tarry certain days.
I know it can be divisive to make dogmatic statements that are not found in the scriptures such as "..with the initial evidence of speaking in tongues" however if we take a step back and reexamine the question "What is the biblical pattern that occurred in the book of Acts when believers were Baptized in the Holy Ghost?" And I think we can safely say "most of the time they spoke in tongues." Remember this is not the born again experience but a separate secondary work of grace. At least it appears to be so when we examine the scriptures.