In what language did the crowd at Lystra shout that the gods had come down in human form?

Answer: Lycaonian

After Paul healed a lame man, the crowds shouted in the Lycaonian language (KJV: the speech of Lycaonia).

“When the crowds saw what Paul had done, they lifted up their voices in the Lycaonian language: “The gods have come down to us in human form!””— Acts 14:11 (BSB)