Update README.md

Author: AlexanderHodicke

ai-and-app-modernisation/ai-services/ai-language/README.md

@@ -43,6 +43,7 @@ OCI Language is a cloud-based AI service for performing sophisticated text analy
 - [Oracle AI Language on oracle.com](https://www.oracle.com/uk/artificial-intelligence/language/)
 - [Oracle AI Language documentation](https://docs.oracle.com/en-us/iaas/language/using/language.htm)
 - [Oracle AI Language blog announcement](https://blogs.oracle.com/ai-and-datascience/post/announcing-oci-language)
+- [Aon improves customer experience with OCI Language service](https://www.oracle.com/customers/aon-case-study/)
 
 ## Customer Stories