Conversion rate optimization (CRO) for multilingual WordPress sites is even more important (and challenging!) than for single language sites. Each language in the site targets a different speaking and cultural community, so what works for one of them may not work for the rest. A proper CRO strategy requires creating site-level split tests as usual (to optimize the site in any language, e.g. theme or widget tests) followed up by language-specific tests for further local optimization.
Remember that multilingual support is not part of the WordPress core features, that is, WordPress does not support a bilingual or multilingual website out-of-the-box. There are however many plugins that extend WordPress with this functionality. Among them, three of the most popular ones are qTranslate, Polylang and WPML . Let’s see how Nelio A/B testing integrates with each of them.
A/B Testing with qTranslate
qTranslate is a multilingual WordPress plugin that stores all languages alternatives for each post in the same post. Therefore you can split test your qTranslate-based multilingual site similarly as you’d do when testing any normal page/post. In this case, this involves:
- Defining the content of your post, including all language variants (e.g. an English and a Spanish version).
- Creating a new A/B test for the post using the standard Nelio interface.
- Indicating the post variants you want to test. For each variant you’re free to change only some of the language versions (e.g. you could only change the English version, the Spanish one, or both) depending whether you want to focus your test on a specific language community. Obviously, to get concistent results, all variants should modify the same language versions (e.g. it doesn’t make sense to test a variant where only the English version has been modified against another variant where only the Spanish one was modified).
- Let Nelio calculate and inform you about the best variant for your site and make sure your site only uses that one from now on with our 1-click update.
Thanks to the fact that Nelio is a native WordPress service, the interface you’ll see when editing a test alternative is exactly the same you’ll see when creating the original qTranslate post, that is, you’ll see the same extended interface to easily indicate the different language versions for the post, the title, and the content.
A/B Testing with WPML
WPML is the most popular commercial multilingual WordPress plugin. Instead of storing all language alternatives for each post in the same post body, WPML creates a different post entry per language and then links them together to create the multilingual site. Therefore, with WPML you have to create as many different split tests as language versions you’d like to improve.
The first step is to set as the active language the one you would like to test. This is simply done by switching languages in the WPML language menu on top of your dashboard
This will filter the posts you see when creating an A/B test for posts or pages to show only those in the selected language. Once you choose the post to test, the rest of the process is no different from an A/B test for a normal post/page. Only visitors accessing the site using the selected language will participate in the test, the other language versions will display as usual for the rest of the visitors.

Nelio A/B Testing
I was very impressed by the quality of this plugin, how easy it was to set up, and the outstanding support Nelio provides. I highly recommend Nelio A/B Testing.

Josette Millar
A/B Testing with Polylang
Polylang is quickly becoming the most popular free multilingual plugin for WordPress, surpassing qTranslate in the process. As WPML, Polylang also stores each language version in a different post and cross-links them.
Since Polylang does not add automatic language filters in the WordPress admin interface, A/B testing those posts is no different than any other post. All different language versions will appear as separate posts in the post/page experiment creation page. Just choose the language version you’d like to test in the dropdown list and you’re ready to go.
Featured Image by GSM World.
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