The twins never told each other that they loved each other. It was not their way, to speak of feelings, and to speak of love towards any of their siblings, even each other, would seem awkward and strange to them, as well as wholly unnecessary. They knew that they loved each other; they conveyed it multiple times a day with understood looks and touches, with embraces and caresses, both sensual and soft; they could have a conversation without using words at all, and they knew without a doubt that they would kill or die for each other, that they would allow nothing to come between them, even their other siblings. They knew they loved each other; so what, then, would be the point to say it aloud?
Words were used best for taunting and manipulation, conveying information or giving commands; emotions and known facts were not necessary to put into words, and so they did not.
It was the same with conveying compliments. They knew that they were attractive and attracted to each other, that they admired each other's appearance; why say so aloud, when they could show it that much more effectively and efficiently with their bodies? Why would Wendell feel the need to tell Darlene that he thought her more than intoxicatingly sexy, more than wickedly creative and perverse in her skills, but also beautiful? The only girl among her brothers, the person he had loved most from the moment of their birth…why would he need to tell her that sometimes when he looked at her, everything about her seemed to shine so brightly to his eyes that it almost hurt to look at her, that everything about her made him feel like he was shining back at her, reflecting and even taking on her glow?
It would sound ridiculous, even if it happened to be true; it was words that conveyed nothing of the reality, when simply taking her by the arms, pushing her against the wall, and kissing her until she couldn't breathe could get the point across considerably better. And so time and time again, this was exactly the option Wendell chose.