The preferred programming environment for developing machine learning applications is often Python. Its rich libraries, such as TensorFlow and PyTorch, provide powerful tools for model development. Additionally, Python's simplicity and readability make it accessible for both beginners and experts. Other environments, like R or tools like Jupyter Notebook, are also popular for exploratory data analysis and prototyping. Overall, the flexibility and robust community support around Python make it a top choice for machine learning development.