Charles Ellicott Commentary Numbers 12:6

"And he said, Hear now my words: if there be a prophet among you, I Jehovah will make myself known unto him in a vision, I will speak with him in a dream." — Numbers 12:6 (ASV)

If there is a prophet ... — Better, If there is to (or, among) you a prophet of Jehovah, I will make myself known to him in a vision, and speak to him. The Septuagint and Vulgate connect the word “Jehovah” with the former, not with the latter part of the clause. The mode of communication between God and Moses differed in the respects which are enumerated in Numbers 12:8 from the mode of communication by visions or dreams, in which God communicated His will to others.