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Back 🧠 What is Natural Language Processing (NLP)? 12 Apr, 2025

Here's a concise yet comprehensive explanation of Natural Language Processing (NLP), including key terminologies, preprocessing steps, and dependencies.


🧠 What is NLP?

Natural Language Processing (NLP) is a field of Artificial Intelligence (AI) that enables machines to understand, interpret, and generate human language. It bridges the gap between human communication (natural language) and machine understanding.


🧾 Common Terminologies in NLP

Term Description
Token Smallest unit of text (word, subword, or character).
Corpus A large collection of text data used for training or analysis.
Stop Words Common words (like a, the, in) often removed as they add little meaning.
Stemming Reducing words to their root form (e.g., running → run).
Lemmatization More accurate root word extraction using vocabulary and morphology (e.g., better → good).
Bag of Words (BoW) Represents text by word frequency, ignoring grammar and order.
TF-IDF Stands for Term Frequency - Inverse Document Frequency; measures word importance.
POS Tagging Assigning grammatical labels to words (e.g., noun, verb).
NER (Named Entity Recognition) Identifies proper nouns like Person, Organization, Location.
Embedding Vector representation of words (e.g., Word2Vec, GloVe, BERT).

⚙️ NLP Preprocessing Steps

  1. Text Cleaning

    • Lowercasing

    • Removing punctuation, numbers, and special characters

  2. Tokenization

    • Splitting text into individual words or subwords

  3. Stop Words Removal

    • Filtering out frequently used but uninformative words

  4. Stemming/Lemmatization

    • Converting words to their root/base form

  5. Vectorization

    • Converting text to numerical format using BoW, TF-IDF, or embeddings

  6. POS Tagging / Chunking / NER

    • Further linguistic parsing for understanding context


🔗 Dependencies and Libraries

Library Use Case
NLTK Classical NLP toolkit; tokenization, stemming, POS tagging, etc.
spaCy Fast NLP pipeline with efficient tokenization, NER, POS, and lemmatization
TextBlob Simple API for basic NLP tasks
Gensim Topic modeling and document similarity (e.g., LDA)
Scikit-learn ML models and feature extraction (e.g., TF-IDF vectorizer)
transformers (HuggingFace) Pretrained language models like BERT, GPT, etc.
TfidfVectorizer / CountVectorizer Feature extraction tools from sklearn.feature_extraction.text