To access multiple Azure AI capabilities (e.g., Speech and Language) using a single endpoint and a single set of credentials, you should provision an Azure AI multi-service resource (called Azure AI service in the portal; formerly "Cognitive Services" multi-service account). This resource provides one endpoint and one key (or Microsoft Entra ID) that authorizes calls across supported services, including Speech and Language. Creating separate "Azure AI Speech" or "Azure AI Language" resources would give you distinct endpoints/keys for each, which does not meet the requirement. Azure AI Content Safety is unrelated.
Microsoft References
Azure AI services multi-service resource (single endpoint/credential across services).
https://learn.microsoft.com/azure/ai-services/multi-service-resource
What are Azure AI services (overview of consolidated access model).
https://learn.microsoft.com/azure/ai-services/what-are-ai-services