Lecture 1
Introduction to
Computational Linguistics
Dr. Radhika Mamidi
ENG 270
What is Linguistics?
• The scientific study of human language
• Aim is to establish a theory by studying nature of a
language and by applying this established theory to
describe other languages
• Descriptive study not prescriptive
• Speech activity - speaker, hearer, setting, code,
medium; plus topic, contextual knowledge, abiding
social norms, communicative competence
Applied Linguistics
Subfields / Inter-disciplinary fields:
Computational Linguistics
Language Teaching/Learning
Translation Studies
Anthropological Linguistics
Note: Now ‘Applied Linguistics’ is associated with Lg teaching.
What is Computational linguistics?
Computational linguistics is an
interdisciplinary field dealing with the
statistical and logical modeling of natural
language from a computational
Goal of Computational linguistics
• To make the computers understand human
• To use technology to build language tools.
• Use computers to process or produce human
We want to communicate with computers in the
language we speak!
Why Computers should talk with us?
• The main obstacle in the interaction between
human and computer is communication
• Computers do not understand our language
and learning computer language is difficult.
• Computer language do not match the
structure of human thought.
• The use of human language in computer
applications will benefit the user.
Most interesting CL application: chatbot
• A chatterbot (or chatbot) is a type of
conversational agent.
• It is a computer program designed to simulate
an intelligent conversation with one or more
human users via auditory or textual methods.
• It is a computer program with artificial
intelligence to talk to people through voices or
typed words.
Computational linguistics is an interdisciplinary field. It takes input from different fields.
Cognitive Science
Computational Linguistics
Computer Science
Relation of CL to Other Disciplines
• Artificial Intelligence (notions of representation, search)
• Machine Learning (probabilistic or statistical techniques)
• Human Computer Interaction (HCI)
• Linguistics (Syntax, Semantics etc.)
• Information Retrieval
• Philosophy of language (formal logic)
• Electrical Engineering (Optical Character Recognition)
• Psychology (insight into learning of linguistic constructions)
Computational Linguistics
is closely related to…
Natural Language Technology
Natural Language Engineering
Natural Language Processing
Artificial Intelligence
Some Applications of
Computational Linguistics
Spelling and Grammar Checkers
Screen readers for the blind
Machine readable Dictionaries
Machine Translation Systems
Question-Answering Systems
Information Retrieval
Information Extraction
Automatic Summarization
Example Application- Search Engine
Example Application- Spelling Checker
Example Application- Grammar Checker
Example Application- Question Answering
Example Application- Machine Translation
Assignment 1
Due date: After 2 weeks
Write short essays [about 8-10 sentences] on the
following topics:
Spelling and grammar checkers
Your favorite search engine
You and a chatbot
You have to include examples, urls, references, sample data
etc. wherever necessary. Don’t forget to add
Marks will be deducted if any kind of plagiarism is found.

Knowledge Engineering