How do you build a bilingual (PL/EN) website that ranks?
A bilingual Polish/English site ranks when each language is a fully translated, separately optimised version living under one domain — Polish at the root, English at /en/ — wired together with correct, bidirectional hreflang tags. Translated pages are not duplicate content; done right, they share ranking signals, so a strong English page can lift its Polish twin (Google Search Central, 2025).
That's the whole answer. The rest of this article is the detail that separates a bilingual site that quietly outranks competitors from one that confuses Google and gets neither language indexed properly.
Why bother with two languages at all?
Because the Polish market is large, online, and Google-dominated. Poland had 35.75 million internet users at 88.1% penetration as of January 2024 (DataReportal, Digital 2024: Poland), and Google holds roughly 96–97% of search there (StatCounter). At the same time, Poland sits in the "High Proficiency" band of the EF English Proficiency Index, especially among under-35s — so a slice of your audience will happily read, search, and buy in English.
Two languages let you meet both. But each language has to earn its ranking on its own. There is no shortcut where translating once gets you found twice.
Subdirectory, subdomain, or separate domain?
For almost every business with two languages, the answer is subdirectories on one domain: twojafirma.pl/ for Polish, twojafirma.pl/en/ for English.
Google documents subdirectories, subdomains, and country domains as all valid, but flags URL parameters like ?lang=en as "not recommended" (Google Search Central, 2025). The reason subdirectories win for a small site: one domain means every backlink, every share, every bit of authority feeds a single property instead of being split across two. Subdomains and separate .pl / .com domains make sense only at large scale or with genuinely separate brands. This is exactly the kind of trade-off we settle before writing a line of code — picking the structure that compounds, not the one that fragments your authority.
What is hreflang, and why does it decide whether you rank?
hreflang is a small tag in each page's <head> that tells Google "here is the same page in another language." It's how Google knows your Polish and English pages are a coordinated pair, not rivals competing for the same spot.
Get it right and the two versions reinforce each other. Get it wrong and Google may treat them as competitors or ignore the connection entirely. And wrong is the norm:
An Ahrefs study across 374,756 domains found 67% of hreflang implementations contain errors — most often missing return links, wrong language codes, or pointing at the wrong URL (Ahrefs).
The rules that fix that 67% are simple but unforgiving:
- Bidirectional. If the Polish page points to the English one, the English one must point back. One-way tags are silently ignored (Google Search Central, 2025).
- Self-referential. Each page should list itself in its own hreflang set.
- Fully-qualified URLs (
https://...), pointing only to canonical pages. - An
x-defaultfor everyone whose language is neither Polish nor English — usually the English version.
We treat hreflang as a build rule, not a nice-to-have, and validate it at build time so a missing return link can't ship silently. When two-thirds of the web gets this wrong, getting it right is free ranking.
Does translated content count as duplicate content?
No. This is the worry that stops people, and Google answers it plainly: "Localized versions of a page are only considered duplicates if the main content of the page remains untranslated" (Google Search Central, 2025). Fully translated pages are distinct content.
In fact, around 29% of the web is duplicate content, which Google handles algorithmically without penalty for legitimate cases (Moz). Properly hreflang-linked translations don't just avoid harm — they share ranking signals, so strength in one language lifts the other (Ahrefs).
What does hurt: half-translated pages (Polish body with English buttons), identical untranslated text served at two URLs, or thin machine translation nobody reviewed. Translate properly, or don't translate that page at all.
Should the site detect a visitor's language and redirect them?
No. Google explicitly warns: "Avoid automatically redirecting users" between language versions (Google Search Central, 2025). Auto-redirects trap VPN users, travellers, and shared computers in the wrong language — and Googlebot, which crawls from US IP addresses, may never reach your Polish content at all.
The right pattern is to suggest, never force: detect the browser language, show a small dismissible banner ("Looking for English?"), and let the visitor choose. The URL then carries the choice from there.
Where does the language switcher go?
In the header first, footer second. UX research is clear that most users look for language controls at the top of the page, and head to the footer only if they can't find them there (Smashing Magazine, 2022). A few rules we build to every time:
- Use native names — "Polski" and "English" — never abbreviations. Chrome's auto-translate can turn "PL" / "EN" into gibberish; full words are immune.
- Never use flags. Flags are countries, not languages.
- Keep it outside the mobile hamburger menu, with a tap target of at least 44×44px (WCAG 2.5.8).
FAQ
Should Polish or English be at the root URL?
Default to your primary audience. For a Poland-first business, Polish lives at the root and English at /en/. For an international product, flip it. Either works — the structure just has to match where your customers actually are.
Do I need to translate every blog post into both languages? No. Translate cornerstone pages (services, key posts) into both, and allow language-specific posts beyond that. Polish and English buyers search for different things, so separate editorial calendars are fine. Just never show a "switch to English" link that leads to a page that doesn't exist.
Do AI search engines like ChatGPT and Google AI Overviews need special markup?
No. Google states you apply "the same foundational SEO best practices for AI features as you do for Google Search overall" (Google Search Central, 2025). AI engines are language-aware: Polish queries pull from Polish content, English from English. Optimise both versions well and add inLanguage to your structured data — there's no separate AI step.
Can I just machine-translate the whole site? You can, but unreviewed machine translation reads as thin content and can trip quality signals. Translate factual pages directly; transcreate persuasive copy, because Polish business writing is more formal than English and a literal CTA often lands wrong.
These are the numbers and rules we design around when we build a bilingual site — fast, found, and tuned to convert in both languages rather than guessed at. If you're weighing a Polish/English site and want it done to this standard from the first commit, book a call and we'll talk through the right structure for your business.