Pick the Right URL Structure
Where each language sits in your URLs affects how search engines understand the site. There are three common options, and one of them is the obvious default:
- Subdirectories (example.com/ja/): recommended, and what we use. You keep one domain and one pool of authority, and it is simple to run.
- Subdomains (ja.example.com): workable, but they split the site into parts that search engines treat as partly separate.
- URL parameters (?lang=ja): best avoided, because they are messy for users and unreliable for search engines.
Translate the Whole Page or Don't Publish It
A common shortcut is to translate the navigation and buttons and leave the main content in the original language. Search engines judge a page's language by its visible content, so these pages look like near-duplicates in the wrong language, and a pile of thin, half-translated pages can lower how the whole site is rated.
Only publish a page in a language if you can make it useful in that language. A smaller site that is fully translated does better than a complete one that is half translated.
Hreflang in Plain Terms
Hreflang is a tag that tells search engines "this page also exists in Japanese, over here", so an English searcher gets the English page and a Japanese searcher gets the Japanese one.
Three rules cover most of what goes wrong:
- Every page lists all of its language versions, including itself.
- Links must be reciprocal. If the English page points to the Japanese one, the Japanese page has to point back, or both are ignored.
- Declare an x-default version for searchers who match neither language.
Write for the Culture as Well as the Language
Direct translation produces text that is technically correct and completely unconvincing. Japanese business writing uses politeness registers, and readers expect thoroughness, so company details, explanations of the process and reassurance all matter. English readers expect directness and text they can scan, and they lose patience with ceremony.
Practical details matter too, such as date, currency and phone number formats, and even line breaks. Japanese text wraps differently, so a layout that looks elegant in English can break awkwardly in Japanese.
Don't Force-Redirect by IP or Browser Language
Automatically sending every visitor to the language your server guesses is a common mistake. Search engine crawlers mostly visit from US servers with English settings, so if you redirect them, they may never properly see your Japanese site. Travelers and international residents also often want the "other" language.
Offer the choice instead. Put a visible language switcher on every page, and at most show a one-time prompt that remembers what the visitor picked.
What This Looks Like in Practice
This site uses the setup described above. Japanese lives in the /ja/ subdirectory, every page is fully translated including titles and descriptions, reciprocal hreflang with x-default appears in both the HTML and the sitemap, and the copy is written separately for each audience instead of translated line by line.
None of this is unusual, and most of it comes down to discipline. Most bilingual sites skip that discipline, which is why doing it properly gives you an advantage.