In Sellars’s view, thought is prior to language in the order of being, but language is prior to thought in the order of knowing. That is, linguistic utterances are normally the product of internal thinking activity, which they express.  The Ryleans in Sellars’s myth have thoughts that are expressed in their utterances, but they don’t realize that they have such inner states.  They have the notion of a meaningful utterance before generating the notion of a meaningful thought, modeled on the former notion. Thus, language is prior to thought in the order of knowing.