From its inception, Slavonic was something of an artificial language, meant to be comprehensible to the majority of Slavic tribes...
Like this modern artificial language,
Slovio/Slavsk [
slovio.com], which AFAIK like all modern artificial/international languages has never caught on (people don't need them; they learn English) but is interesting to linguists and today's Slavophiles. It's like a Russian-based creole, simplified and easy to understand. My guess is if you learn this, a native Russian speaker could understand you.
