I decided to throw together a sketch of a language (using Russian
lexis) to test out my musings on marking case strictly on articles but
disallowing personal / proper-noun articles.

For simplicity, I've just got one article that encodes nothing but
case (easily expanded to have lots of different articles for
definiteness or whatever), and cased pronouns based on the Russian
pronoun chart:
	Trig		Acc		Dat		Instr		Nom		Gen
Art	Tot		To		Tu		Toj		Tom		Tov
He	On		Jevo		Jemu		Im		Jom		Jovo
She	Ona		Jejo		Jeju		JIj		Jej		Jojo
I	Ja		Menja	Menju	Menoj	Menje	Monja		
Rel.	Koj		Koj		Kojemu	Kojim	Kojom	Kojovo

Now, we need voice-changing constructions that allow any argument to
promoted a subject position, because that's the only syntactic
position that proper nouns can occupy. I decided to play with a
heterogenous system of different syntactic voice constructions that I
might somehow be able to explain as being logically derived from
circumlocutions in the pre-existing language, because that's more
complicated, and therefore more fun, than a morphological trigger
system. Conveniently, the Russian prepositional case is never used "by
itself", without a preceding preposition, so the construction of
free-standing prepositional case is open to be hi-jacked as an oblique
case for marking demoted subjects with no risk of ambiguity (as might
occur if we used, say, the instrumental case). Thus, I have re-named
Prepositional as Nominative and Nominative as Trigger.

The Voice Constructions:
Active:
	normal conjugation
Accusative Trigger:
	byt (stem)+en
Dative Trigger:
	luchat (inf.)
Instrumental Trigger:
	byt (stem)+jush
Genitive / Oblique Trigger:
	byt (prep) (art) (stem)+nost
	
~~Examples Demonstrating Different Strategies For Dealing With
Different Numbers of Proper Nouns per Clause~~

"Bob introduced Mary to Alice."

*Topicalization, Active Voice, and Accusative Relativization
Mary, Bob poznakomil jejo tu zhenshina, kojom zven Alice.
Mary, Bob introduced her-ACC the-DAT woman, who-NOM  0-cop. called Alice.

*Topicalization & Reciprocal with Accusative Voice
Bob, jom byl poznakomen Alice i Mary tu drugdrug.
Bob, he-NOM was introduced Alice and Mary the-DAT each-other.

*Topicalization & Reciprocal with Dative Voice
Bob, jom luchal poznakomit Alice i Mary to drugdrug.
Bob, he-NOM got introduced Alice and Mary the-ACC each-other.

"England sent Nigel to Germany."

*Topicalization & Coordinated Predicates with Active & Dative Voices
Nigel, jevo England poslal i Germany luchal poslat.
Nigel, him-ACC England sent and Germany got send.

"I gave Bob the book."

*Dative Voice
Menje Bob luchal dat to kniga.
I-NOM Bob got give the-ACC book.

"Mary gave Bob the book."

*Topicalization & Active Voice
Bob, jemu Mary dal to kniga.
Bob, him-DAT Mary gave the-ACC book.

"Mary gave Felix to Bob."

*Topicalization, Dative Voice, and Accusative Relativization
Mary, Bob luchal dat to kot, kojom zven Felix, jej.
Mary, Bob got give the-ACC cat, who-NOM 0-cop. called Felix

*Topicalization & Coordination with Active & Accusative Voices
Bob, jemu Mary dal i Felix byl den.
Bob, him-DAT Mary gave and Felix was given.

"I left with Jack."

*Oblique Voice
Menje Jack byl c toj vyjdnost.
I-NOM Jack was with the-INSTR leaving.

"I killed the mouse with Felix."

*Instrumental Voice
Menje byl ubjush to mysh Felix.
I-NOM was killing the-ACC mouse Felix.

"I killed Felix." vs. "I did not kill Felix" (making use of the
Russian genitive direct object for negatives)

*Accusative Voice vs. Oblique Voice
Menje byl uben Felix. vs. Menje ne byl tov ubnost Felix.
I-NOM was killed Felix. vs. I-NOM not was the-GEN killing Felix.

-l.