The language, communicated by Sai, that consists of gestures used to signify something (four splayed fingers mean "blue"), noises used in place of words, symbols, facial expressions, newly-created words (such as "mamble"), and distorted words (like "peeja").
Yes, "Saieese" does have four vowels in a row, but so does "onomatopoeia."
BBT literally stands for "baby boy toy." He is a headless mannequin with whom one has sex, and is traditionally younger than the cougar who uses him. An encounter with BBT does not include feelings or intelligent conversation. He is a toy.