intelligible

intelligible
/ɪnˈtelɪdʒəbl; ɪn`tɛlɪdʒəbl/ adj
that can be (easily) understood 可（易）理解的
    intelligible speech 明白易懂的讲话
    a muddled explanation which was scarcely intelligible 难以理解的胡涂解释.

牛津英汉双解词典