14 y/0 sister randomly giggles, bites lips until it bleeds, left leg shaking, since age 7 but now worse, can it be tourettes or something?

Souds like autism. Developmental delays are commonly associated with mental retardation and stereotypic or repetitive behavior at times self injurious in nature. More than likely your sister has autism but to be sure she has to be examined by a trained health professional. Tourette's usually presents differently.
Many possibilities . She could be normal, she could have adhd, anxiety dosorder, developmental problems, or something else. But the symptoms aren't typical of tourette's. If it concerns your parents, then she should be evaluated.