Celebrity Celebrity Family Celebrity Babies Elon Musk Explains How to Pronounce Son X Æ A-12's Name, Says Grimes 'Mostly Came Up' with the Idea Elon Musk and Grimes welcomed baby boy X Æ A-12 on May 4 By Gabrielle Chung Updated on May 7, 2020 08:10PM EDT Elon Musk is breaking down the proper pronunciation of his son X Æ A-12's unique name. The Tesla CEO, 48, explained how to correctly address the newborn during Thursday's episode of The Joe Rogan Experience podcast. While speaking about his newborn, Musk shared that girlfriend and new mom Grimes was actually the one who "mostly came up with the name." "Yeah, she's great at names," he said. According to Musk, X is spoken "like the letter" while "the 'Æ' is pronounced like 'ash.' " The Space X founder went on to proudly proclaim that the A-12 part of his son's name was his idea, saying that he wanted to pay homage to the Lockheed A-12 reconnaissance aircraft built by the United States Central Intelligence Agency. "A-12 was my contribution," he said. "The Archangel-12, the precursor to the SR-71, the coolest plane ever." Elon Musk Corrects Grimes' Explanation of Their Son's Name – and the New Mom Is Not Impressed Musk and Grimes, 32, welcomed X Æ A-12 on Monday. The child is the first for Grimes while, Musk has five sons from a previous marriage. His first son, Nevada, died tragically of SIDS at 10 weeks old in 2002. Elon Musk and son X. Elon Musk Twitter During his appearance on The Joe Rogan Experience podcast, Musk also opened about becoming a father again, telling the host, "Actually, I think it's better being older and having a kid." "I appreciate it more," he said. "Babies are awesome. They're awesome." "They're little lovebugs," the dad added. "It's wonderful. It's great." Musk and Grimes were first romantically linked in May 2018. Elon Musk and Grimes. Neilson Barnard/Getty Singer Grimes Says She Loves Elon Musk: He's a 'Super-Interesting' Person While the name of their new baby boy, X Æ A-12, is technically legal, a family law attorney recently told PEOPLE that it won't be accepted by the state of California as a valid moniker. "In California, you can only use the '26 characters' of the English language in your baby name," David Glass said Wednesday. "Thus, you can't have numbers, Roman numerals, accents, umlauts or other symbols or emojis. Although an apostrophe, for a name like 'O'Connor,' is acceptable." Glass said that if X Æ A-12's birth certificate is submitted as-is, it is sure to be rejected and Grimes and Musk will be asked to re-submit it. "They have an opportunity to appeal the rejection of the birth certificate application but it's unlikely that it will be granted because, again, California ... has been struggling with using symbols," Glass added.