Maxis, the developer behind The Sims, originally wanted all the sims to speak English. Technical limitations prevented that and the team had to use a fallback option—gibberish, or "Simlish," based on obscured language such as Navajo or Esperanto. That tidbit is just one of the many revelations from a series of design documents and a video The Sims programmer and artist Don Hopkins released earlier this week.
This is a companion discussion topic for the original entry at https://www.vice.com/en_us/article/j5w7w8/the-original-blueprints-for-the-sims-reveal-why-the-game-always-included-gay-relationships