There was a medical case of an American woman, she was in a coma, once she came out of the coma, she started to speak with a British accent, so, not surprising this lovely Russian lady can suddenly speaks Thai. Twenty years living in Thailand is a big help, too, because certain part of her brain stores the perfect Thai accent from hearing it for so long, in her memories. Triggered by the fall off the stairs, brings this one stored memory to the surface. Life is a mystery, indeed, but good on her.