Okay, habe es selber gefunden. Für alle, die es interessiert:
public function collect(CmsSlotEntity $slot, ResolverContext $resolverContext): ?CriteriaCollection
{
$criteriaCollection = new CriteriaCollection();
$criteria = new Criteria([$resolverContext->getSalesChannelContext()->getLanguageId()]);
$criteriaCollection->add('language_' . $slot->getUniqueIdentifier(), LanguageDefinition::class, $criteria);
return $criteriaCollection;
}
public function enrich(CmsSlotEntity $slot, ResolverContext $resolverContext, ElementDataCollection $result): void
{
$languageSearchResult = $result->get('language_' . $slot->getUniqueIdentifier());
$language = $languageSearchResult->first()->getName());
...
}
Viele Grüße, Frank