Final answer:
Charles Parham is the Pentecostal leader who first taught that speaking in tongues is the initial evidence of the baptism in the Holy Spirit.
Step-by-step explanation:
The Pentecostal leader identified as being the first to teach that speaking in tongues is the initial "Bible evidence" of the baptism in the Holy Spirit is a) Charles Parham. He was an American preacher and evangelist who significantly contributed to the beginning of the modern Pentecostal movement. Parham believed that the speaking in tongues was a sign that an individual had received the Holy Spirit, a view that later became a standard doctrine in Pentecostalism.