EXPOSITION
Cornelius and his household received the message God had for them through Peter. As they listened attentively, the Holy Spirit fell on them and they began to speak in other tongues. One sign that followed the Jews when the Holy Spirit fell on them on the day of Pentecost was speaking in tongues as the Holy Spirit gave them utterance.
It means it is only the Holy Spirit who can empower you to speak in tongues.
LESSON LEARNT: One can only speak in tongues after being baptized in the Holy Spirit.