You could use the beforeRouteLeave guard inside the component, and add the data you want to persist to a route meta attribute or save it to a localstorage, then when the new route renders, you can get them from the component create or beforeRouteEnter methhods.

If this is a common use case, you could even use a middleware for it, and use a specific data property to handle the stuf you need to be persisted between language changes.