It appears that any 4yo conversing and or interacting with an 8yo is the 'real' issue here. Good or bad....this shouldnt be happening without adult supervision and to think otherwise is living life on the edge. As an adult you've set yourself up as a victim in defensive mode and one should be making the assertive move by either relocating the play area so that an adult can monitor more closely or you can chug a brewski in the lazy boy while your kid plays happily in the confines of a brick walled front yard.(sarcasm)
You can write letters....speak with other ugly mom and dad but it aint gonna change the world nor your little neighborhood.
The one thing you can change is the environment in which you as a parent dictate and can happily control.
