ēmma
The modifier Ä“mma refers to the outside of something. So, rÅ« NP Ä“mma is from the outside of NP or out of NP. The expected expression rÄ NP Ä“mma is not used. The word Ä“mma is related to yesterday’s word mÄ“.
rūjēmma
Likewise rÅ«jÄ“mma is rÅ« NP Ä“mma without a specified location, and so means ‘out’. The expected expression rÄjÄ“mma is not used.
I wonder if young children say rÄjÄ“mma? 🙂
Oh, good question! I would think that they do. It’d certainly be a beginning language learner mistake.