GPT-4o ('o' stands for 'omni') represents a significant advancement in human-computer interaction. It can accept any combination of text, audio, images, and video inputs and generate any combination of text, audio, and image outputs. Its response time for audio input is extremely fast, averaging only 320 milliseconds, comparable to human conversational response times. It has made significant progress in processing non-English text, while also being faster and 50% more cost-effective on its API. GPT-4o also excels in visual and audio understanding compared to existing models.