Which muscle elevates the posterior portion of the soft palate?

The levator veli palatini, as its name suggests, is the primary muscle that elevates the soft palate (important for velopharyngeal closure during swallowing/speech). Palatoglossus and styloglossus are tongue-related muscles, and tensor veli palatini primarily tenses the soft palate and opens the Eustachian tube, rather than elevating the palate.