Which of the following services is used for voice recognition capabilities in Azure?

The Azure Speech Service is the correct choice for voice recognition capabilities in Azure because it is specifically designed to convert spoken language into text. This service encompasses various functionalities, including speech-to-text and text-to-speech capabilities, enabling applications to utilize voice input effectively.

Azure Speech Service also supports real-time speech recognition, making it suitable for interactive applications, and provides customization options to enhance accuracy based on user requirements and scenarios. This makes it a powerful tool for developers looking to integrate voice interactions in their applications.

In contrast, the other options do not focus on voice recognition. Azure Vision API is tailored for image processing and analyzing visual content. Azure Language Understanding (LUIS) is aimed at natural language processing, allowing applications to understand and interpret human language but does not handle voice input directly. Azure Text Analytics provides insights from text data but is not involved in processing spoken language. These distinctions highlight why the Azure Speech Service is the go-to option for voice recognition functionalities within Azure.