Criminals on the Cross

Did Jesus say anything to any other human being while on the cross?
Yes, to one of the two criminals on the crosses next to Him, as recorded in Luke 23:39-43: 39 And one of the criminals who were hanged blasphemed Him, saying, “If You are the Christ, save Yourself and us.” 40 But the other, answering, rebuked him, saying, “Do you not even fear God, seeing you are under the same penalty? 41 And we indeed justly, since we are getting what we deserve for what we did; but this Man has done nothing wrong.” 42 Then he said to Jesus, “Remember me, Lord, when You come into Your kingdom.” 43 And Jesus said to him, “Truly, I say to you, today you will be with Me in Paradise.” The corresponding account in Matthew adds a little more color: 38 Then two robbers were crucified with Him, one on the right and another on the left. 39 And those passing by kept blaspheming Him, wagging their heads 40 and saying, "You who destroy the temple and build it in three days, save Yourself! If You are the Son of God, come down from the cross.” 41 Likewise the chief priests also, mocking with the scribes and elders, said, 42 “He saved others; Himself He cannot save. If He is the King of Israel, let Him now come down from the cross, and we will believe Him. 43 He trusted in God; let Him deliver Him now if He will have Him; for He said, ‘I am the Son of God.'” 44 Even the robbers who were crucified with Him reviled Him with the same thing (Matthew 27:38-44).

The Gospel of Matthew says both "robbers" reviled Jesus, while Luke says just one of the two did. Which account is correct?
Both are correct. Jesus was on the cross for six hours: "Now it was the third hour, and they crucified Him... And at the ninth hour Jesus cried out with a loud voice..." (Mark 15:25, 34). When first nailed to the cross, both robbers probably lashed out in pain and rage at everyone in sight including Jesus, especially since they saw the chief priests and the crowd insulting Him. As time wore on, however, one of the two recognized Jesus as God by His grace and "rebuked" the other as above.

Who were "those passing by" (Matthew 27:39) Jesus' cross?
Jesus on a towering cross on a picturesque hilltop is an unbiblical fiction of Roman Catholic art. Romans crucified right next to major roads (see Golgotha) on short crosses (see sour wine) so that the bloody sight of the crucified victims can motivate the passersby to fear and submit to Rome.