Different Levels of Language Analysis in NLP


Natural Language Processing (NLP) is a subfield of Artificial Intelligence. NLP provides methods for performing useful tasks with natural languages. To give a feel of a human expert, the computer is needed to interact with the user in natural languages.

What is done in NLP?

Step1: User inputs in form of a natural language.
Step2: It goes to the Natural Language Interface (NLI).
Step3: Output is obtained in a language form that is understood by the application program.

Types of Levels of Knowledge used in NLP:

1. Phonological Knowledge: A phoneme is the smallest unit of sound and relates to the sound of the word.

2. Syntactic Knowledge: It relates to how words are put together to form a grammatically correct sentence.

3. Semantic Knowledge: It relates to the meaning of words and phrases and how they combine to form a meaningful sentence.

4. Morphological Knowledge: It relates to word construction from basic units called Morphemes.

5. Pragmatic Knowledge: It relates to the use of sentences in different contexts and how the contexts affect the meaning of sentences.

6. Word Knowledge: It relates to the language a user must have to understand and carry on a conversation.

Phases of Natural Language:

1. Morphological Analysis: Individual words are analyzed into their components and nonword tokens, such as punctuations are separated from the words.

2. Syntactic Analysis: Linear sequences of words are transformed into structures that show how the words relate to each other. Some word sequences may be rejected if they violate the language’s rules for how words may be combined.

3. Semantic Analysis: The structures created by the syntactic analyzer are assigned meanings. In other words, a mapping is made between the syntactic structures and objects in the task domain. Structures for which no such mapping is possible may be rejected.

4. Discourse Integration: The meaning of an individual sentence may depend on the sentences that precede it and may influence the meanings of the sentences that follow it.

5. Pragmatic Analysis: The structure representing what was said is reinterpreted to determine what was meant.