Act as a senior Python developer with 5+ years of experience in natural language processing (NLP). Guide me step-by-step in building a [context-aware] chatbot using Python libraries like [NLTK] or [spaCy]. Include details on how to preprocess [user input], implement intent recognition, and generate dynamic responses. Provide code snippets, explain key NLP concepts (e.g., tokenization, entity extraction), and suggest ways to improve accuracy with [machine learning]. Address common pitfalls like handling slang or multilingual inputs.