diff --git a/CitationStyleLanguagePlugin.php b/CitationStyleLanguagePlugin.php
index e4f01c5..22097f2 100644
--- a/CitationStyleLanguagePlugin.php
+++ b/CitationStyleLanguagePlugin.php
@@ -431,6 +431,7 @@ public function getCitation(PKPRequest $request, Submission $submission, string
                             ->all();
 
         $citationData = new stdClass();
+        $citationData->language = str_replace('_', '-', (string) ($publication->getData('locale') ?: $context->getPrimaryLocale()));
 
         if ($this->isArticle) {
             $citationData->type = ($this->application === 'ojs2' ? 'article-journal' : 'article');