The testimony of the history of the early church in the book of Acts -- believers were accepted as converted, without the evidence of speaking in tongues.
1. Acts chapters 1 & 2 -- Jesus promises the disciples that they will be baptized with the Holy Ghost in a few days (1:5), and indicates they will receive power to be witnesses unto the uttermost part of the earth (1:8). The promise is fulfilled on the day of Pentecost. The 120 are filled with the Holy Ghost and speak in tongues (2:4). Of this group of 120 (1:15), at least ten of them had already received the Holy Ghost (John 20:20-23), with no corresponding evidence of speaking in tongues. Notice also it is the 120 disciples that speak in tongues (some even believe only the 12 apostles). There is no evidence that the 3000 spoke in tongues, yet they were received as believers and baptized (Acts 2:41-47).
2. Acts 4:4 -- About 5000 believe, with no evidence of speaking in tongues.
3. Acts 8:1-25 -- The account of the outpouring in Samaria records that many believe and were baptized -- and makes specific mention of them receiving the Holy Ghost (v. 17) -- but with no evidence of speaking in tongues.
4. Acts 8 -- Philip preaches/witnesses to the eunuch. The eunuch is converted and there is no mention of speaking in tongues (8:26-40). Yet Philip baptized him and he goes on his way rejoicing.
5. Acts 9 -- Saul (Paul) is converted, his eyesight is restored, and he is filled with the Holy Ghost (9:17-20), with no mention of the initial evidence of speaking in tongues (He does exhibit the evidence of being a witness; cf. 1:8 with 9:20).
6. Acts 10 -- Peter preaches to the household of Cornelius; they believe, they Holy Ghost falls on them and they speak in tongues (10:44-48). Peter likens this experience to the one of the day of Pentecost (11:15).
7. Acts 11:21 -- A great number believe and turn to the Lord. The evidence of speaking in tongues is not mentioned.
8. Acts 13 -- A number of Gentiles believe (vs. 47-48), and are filled with the Holy Ghost (v. 52). Speaking in tongues is not mentioned.
9. Acts chapters 14-18 -- Paul and other disciples travel to numerous places -- such as Lystra, Derbe, Thessalonica, Berea, Corinth, Philippi, Athens. Many are converted, with no mention that they spoke in tongues.
10. Acts 19 -- The disciples at Ephesus receive the Holy Ghost and speak in tongues.
11. Acts chapters 20-28 -- Numerous journeys are made by Paul and others. People are converted. Speaking in tongues is not mentioned.
Looking at records of conversion throughout the book of Acts, speaking in tongues is only mentioned on three occasions -- the day of Pentecost (2:3,4,11), the household of Cornelius (10:46), and the disciples at Ephesus (19:6). The obvious conclusion is that speaking in tongues was not an evidence of receiving the Holy Spirit for the converts in the days of the early church.