By Angie Han Television Critic It is fitting, I guess, that a film about a writer who spends more of her time intellectualizing life than allowing herself to experience it would be better at telling than showing. Lou (Chloë Grace Moretz) is an aspiring YA novelist who stumbles into a lucrative side hustle writing personalized wedding vows. Despite never having been married herself (in fact, she’s fresh off a broken engagement), she discovers a real knack for putting into words both the enormity and specificity of a couple’s love. But if the film, like its heroine, does a decent job of explaining emotions, it has a harder time projecting them — such that even the grand third-act gesture feels more like a concession to a tried-and-true narrative formula than a spontaneous act of ardor. Lou begins Love Language, written and directed by Joey Power and debuting at SXSW, in no mood to engage with the trappings of romance.…