https://tts.langeek.co/read?text=Ynk&hash=990d69a806f0f68ddf52b66f92af1e9683ff986b&lang=en&cache-only=0&driver=googletts&accent=US

https://tts.langeek.co/read?text=cmU&hash=ca67201b16edc1785e6f4445a8b98f155d0a87d2&lang=en&cache-only=0&driver=googletts&accent=US

These prepositions allow the speaker to refer to known information to support or elaborate their statements.