Before we get started lets say some foundations.

Each word in an alphabet belongs to its parts of speech (PoS)

Parts of Speech can be divided into different categories:

These come in handy in a variety of applications such as:

Parts Of Speech Tagging

Rule-Based Tagging

Based on a set of rules that define precedence of different parts of speech

Stochastic (probability based)

A popular tools for this is the Hidden Markov Model