OpenAI CEO Sam Altman compared his child’s first attempt at speaking two words together with one of GPT 5.6 discovering new math. In a post on X, he wrote, “our older kid put two words together for the first time and i am approximately as amazed by this cognitive feat as i am by GPT-5.6 discovering new math.” OpenAI introduced the GPT 5.6 family of AI models late last month, with the new lineup including three models: Sol, Terra and Luna. According to the company, GPT 5.6 Sol is its most powerful model so far, Terra is designed for everyday use, and Luna is a faster and more affordable option. OpenAI also said these models include its strongest safeguards to date. However, the new models are not available to everyone yet; OpenAI started with a limited preview for a small group of trusted partners after the US government requested an early preview before a wider release. Altman addressed the delayed public launch on X, writing, “At the request of the US government, it is launching today in limited preview instead of the open access launch we were planning on.” He added, “We are working with the government to get to general availability as fast as we can.”