Natural language processing (NLP) is the branch of AI that lets computers read, understand and generate human language. It powers search engines, chatbots, translation, spam filters and summarisation. Modern NLP is built mostly on deep learning, especially transformer models such as those behind ChatGPT and Claude.
What are the main NLP tasks?
| Task | What it does | Everyday example |
|---|---|---|
| Text classification | Assigns a label to text | Spam or not spam |
| Sentiment analysis | Detects positive or negative tone | Product review analysis |
| Named entity recognition | Finds names, places, dates, amounts | Pulling details out of invoices |
| Summarisation | Shortens long text | Meeting notes |
| Question answering | Answers questions from text | Help-centre bots |
| Translation | Converts between languages | English to Hindi |
| Text generation | Writes new text | Chat assistants |
How did NLP techniques evolve?
- Rules and word counts. Early systems used hand-written rules and counted words (bag of words, TF-IDF).
- Word embeddings. Word2Vec and GloVe represented words as vectors, so similar words sat close together.
- Recurrent networks. RNNs and LSTMs read text in order and captured some context.
- Transformers. Attention let models consider all words at once, leading to BERT, GPT and today's LLMs.
Why is NLP important for India?
India has many languages and scripts, and most people are more comfortable in their own language than in English. Good NLP for Indian languages makes technology usable for far more people, which is one reason building domestic AI capability matters.
How to start learning NLP
- Learn Python and basic machine learning first (Python for AI).
- Try a text classifier with TF-IDF and logistic regression.
- Learn embeddings, then attention and the transformer.
- Fine-tune a pretrained model for a task, then build a retrieval-based app (RAG).
Program Zero teaches this path in Phase 8 (NLP, transformers and building LLMs), including building a custom tokenizer and a GPT-style model from scratch.
