Intelligent voice assistant with GUI

We are looking for an experienced developer with experience in voice assistant development and GUIs to program an intelligent voice assistant. The assistant should be able to understand natural language, answer questions, and perform actions based on user input. The assistant is said to be able to interact with various APIs and services, including but not limited to weather forecasting, music streaming, calendar management, and email integration.
The developer will also be responsible for designing and implementing a responsive user interface that allows users to interact with the voice assistant and see relevant information at a glance. The GUI should be optimized for various screen sizes and resolutions.
Additionally, the developer is expected to optimize the assistant for high scalability and ensure that the voice assistant is able to handle a large number of users. The server-side infrastructure should be designed to be efficient and cost-effective to keep monthly server costs low for the client.
We are looking for a developer with experience in developing voice assistants and GUIs. Experience with artificial intelligence and machine learning is a plus, but not required. The developer should be able to complete the project within 10 months.
Please send your references and work samples to demonstrate your skills and experience.