When three-degree systems of demonstratives where proximal/medial/distal correspond to 1st/2nd/3rd person develop into two-degree systems, the opposition will be proximal&medial vs. distal or proximal vs. medial&distal, corresponding to 1st&2nd vs. 3rd person or 1st vs. 2nd&3rd person. There will never be a two-degree demonstrative system with a correspondence to a person system where the opposition is 1st/3rd vs. 2nd person.
Standardized
When three-degree systems of demonstratives where proximal/medial/distal correspond to 1st/2nd/3rd person develop into two-degree systems, the opposition will be proximal&medial vs. distal or proximal vs. medial&distal, corresponding to 1st&2nd vs. 3rd person or 1st vs. 2nd&3rd person. There will never be a two-degree demonstrative system with a correspondence to a person system where the opposition is 1st/3rd vs. 2nd person.
Cf. #1951.