Overall Design of the System

The overall design of the system would depend on the specific use case and requirements. However, in general, an AI chatbot system would have the following components:

1. User Interface: This is the interface through which the user interacts with the chatbot. It could be a website, mobile app, messaging platform or voice interface.

2. Natural Language Processing (NLP) Engine: This component is responsible for understanding the user's input and generating a response. It uses various techniques like text classification, sentiment analysis, entity recognition, and intent detection to understand the user's input.

3. Knowledge Base: This component is responsible for storing the information that the chatbot uses to generate responses. It could be a database, a set of rules or a machine learning model.

4. Dialog Management: This component is responsible for managing the conversation flow between the chatbot and the user. It decides what response to generate based on the user's input and the context of the conversation.

5. Integration: This component is responsible for integrating the chatbot with other systems or APIs to provide additional functionality. For example, integrating with a payment gateway to enable transactions.

6. Analytics and Monitoring: This component is responsible for tracking the performance of the chatbot and detecting any issues or errors. It helps in improving the chatbot over time.

Overall, the design of the system should be modular and scalable, allowing for easy maintenance and updates. It should also be designed with security and privacy in mind to protect user's data.