YES, it is. Let’s take a look at the several places in the scriptures where people were baptized in the Holy Spirit evidenced by speaking in tongues:
Acts 2:4, “And they were all FILLED WITH THE HOLY GHOST, AND BEGAN TO SPEAK WITH OTHER TONGUES, as the Spirit gave them utterance.”
The very first place where people were filled with the Holy Ghost showed that there was an evidence of speaking in tongues there.
Acts10:44-46, “While Peter yet spake these words, the Holy Ghost fell on all them which heard the word. And they of the circumcision which believed were astonished, as many as came with Peter, because on the Gentiles also was poured out the gift of the Holy Ghost.  For they heard them speak with tongues, and magnify God. “That event happened in the house of Cornelius. The Spirit of God came upon them and they spoke with tongues
Acts19:6, “And when Paul had laid his hands upon them, the Holy Ghost came on them; and they spake with tongues, and prophesied.”
On the basis of scriptural proofs, the evidence of infilling with the Holy Ghost is speaking in tongues.