Russian vocabulary has two useful entry points for a learner: recognizable patterns shared across Slavic languages, and a historical split between everyday Russian words and more formal ones borrowed from Old Church Slavonic.
Russian often has two related words for a similar concept — one native/everyday, one derived from Old Church Slavonic (the historical liturgical and literary language) — with the Church Slavonic form usually carrying a more formal, elevated, or abstract register. Recognizing this pattern helps explain why Russian sometimes has multiple words that feel like near-synonyms but aren't interchangeable in tone.
Like other Slavic languages, Russian vocabulary is often built from recognizable roots combined with prefixes and suffixes that shift meaning in fairly consistent ways — once you learn a handful of common prefixes, unfamiliar words built from a root you already know become easier to guess.
Many pairs trace back to a native everyday word alongside a more formal one borrowed from Old Church Slavonic, the historical liturgical and literary language — the Church Slavonic form usually carries a more elevated or abstract register.
The mechanism is different (prefix/suffix modification of a root rather than Arabic's root-and-pattern system), but the underlying idea is similar: recognizing common prefixes and roots makes unfamiliar vocabulary more guessable.
Often, yes — related Slavic languages frequently share recognizable roots, even where the exact words and grammar differ.
That's the plan, consistent with how Tarc's existing Arabic and Latvian vocabulary lessons are taught.
See also: Russian Grammar · Russian Phrases · Learn Russian