To communicate with an RDBMS (Relational Database Management System), you typically use Structured Query Language (SQL). SQL allows you to interact with the database by performing tasks such as querying data, inserting new records, updating existing records, and deleting records. Additionally, many RDBMS systems also provide APIs (Application Programming Interfaces) that allow you to interact with the database programmatically using various programming languages such as Python, Java, or C#. These APIs provide more flexibility and control over database operations, especially in application development scenarios.