Pharaoh had two dreams and it was only Yosef who was able to interpret them for him. Yosef was taken out of the dungeon where he had been for years and brought before Pharaoh. The Midrash Tanchuma (MiKetz 3) directs our attention to a number of changes that Pharaoh made in relating the dreams to Yosef. According to the Midrash, Pharaoh was testing Yosef to see if he truly had divine inspiration and would know about these changes.
The Midrash lists a number of differences between the actual dreams and the way they were told. One difference the Midrash does not mention, and, in fact, it was the first difference that we can see. In the dream, the Torah says, “…behold he was standing over the river…”, AL HAYE’OR. (Gen. 41,1) When relating the dreams Pharaoh says, “…behold I was standing upon the bank of the river”, AL SEFAT HAYE’OR. (41,17)
There is a verse in Tehillim which is recited every Thursday morning in the SHIR SHEL YOM, the psalm of the day. In part it reads: SEFAT LO YADATI ESHMA, “I heard the speech of one that I knew not.” This is a difficult verse to explain but in usual translations it refers to the Jewish people when they left Egypt they heard the voice of Hashem and did not really comprehend what He was saying.
A literal explanation, however, could be that Yosef, who is mentioned in this verse, claims that he did not hear from Pharaoh the word SEFAT when he was told about the dream. Pharaoh had changed the word SEFAT to AL. This Yosef pointed out was not the correct description of the dream, another indication that he really had divine inspiration.