Certainly, Bat being a young boy, with his mind set on anything other than Soli’s feelings, he was not shrewd enough to understand that Soli was pregnant. This is pronounced as we switch to English: I can see how/why “ur” (seed, offspring in English) could have slipped through. But not getting the gesture when she mentions “child” simply makes Bat what we in Mongolia call “tums”, literally translated as “potato”, someone who is not able to get tact and even obvious elements of human interactions.