Instructions: Formulate comprehensive, detailed answers to the following questions, drawing upon the full depth of the source material.

1. Trace the evolution of Natural Language Processing through its four historical phases. For each phase, describe its primary focus, key developments or systems, and the overall intellectual shift that led to the next phase.
2. Discuss the concept of ambiguity as a fundamental challenge in NLP. Define and provide examples for the five types of ambiguity listed in the text: lexical, syntactic, semantic, anaphoric, and pragmatic.
3. Explain the four primary phases of an NLP pipeline: Morphological Processing, Syntax Analysis, Semantic Analysis, and Pragmatic Analysis. Describe the specific goal of each phase and how it builds upon the output of the preceding one.
4. Compare and contrast the different approaches to Part-of-Speech (POS) Tagging described in the text: Rule-based, Stochastic, and Transformation-based. What are the core principles, strengths, and weaknesses of each methodology?
5. Describe the classical problem of ad-hoc retrieval in Information Retrieval (IR). Compare the Boolean Model and the Vector Space Model as solutions to this problem, detailing their underlying principles, query/document representations, advantages, and disadvantages.