Initiating calls to a specific agent with a predetermined language

I am writing to inquire about the agent_language_override parameter when using the Retell client for outbound calls.

I recently tested this feature by setting the parameter to Spanish (es-419, which is listed as an accepted value in the docs) and providing my specific override_agent_id. However, the call I received was still in English.

Our goal is to use the same agent for all calls while being able to specify the language for each individual call if we have a preferred language on file. Is there a specific way to accomplish this behavior?

For reference, this is how we are currently initiating the calls:

const response = await retellClient.call.createPhoneCall({
      from_number: <SOME NUMBER>,
      to_number: <SOME NUMBER>,
      override_agent_id: RETELL_AGENT_ID,
      override_agent_version: retell_version_number,
      agent_override: {
        agent: {
          language: "es-419",
        },
      },
      retell_llm_dynamic_variables: retellDynamicVariables,
    });

@support2 please help!