A bilingual website needs more than a translation
Make Russian and English versions useful for people and understandable to search systems.
Updated:
A second language serves a new audience when people can complete the important journey: understand the offer, review relevant work and get in touch. A translated menu above untranslated content does not achieve that.
Two versions of one customer journey
Review states as well as pages: form confirmations, errors, image descriptions, documents and navigation. A language switch should lead to the equivalent material when it exists. If an article has no translation, state that clearly rather than presenting the old text under a new language URL.
Search foundations
Each substantial page needs a defined primary URL. Hreflang describes relationships between localized versions; Google explains the rules in its localized page documentation. The markup needs to match what is actually published.
Sitemaps, titles and descriptions should reflect the real pages too. A shared content source for navigation, metadata and publication lists helps prevent drift.
Part of the product
Plan localization early: phrases change length, contact methods can differ and translations may be published later. This makes the site easier to extend without manually rebuilding relationships for every section.