Natural Language in a Nutshell

Rupomcse23

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Apr 17, 2023

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Language:

• Language is a structured system of communication,
• Natural Languages are spoken,
• It can be encoded into secondary media — writing, whistling, signing, braille, etc.,
• Over 5000 human Languages,
• Natural Languages evolve amongst humans,
• Formal Languages are created with well-defined syntax and rules to serve a specific purpose,
• e.g., Computer programming languages.

Spoken Language vs. Written Language:

• Spoken Languages existed forever,
• Written Languages developed only a few thousand years ago,
• Spoken Languages have many nuances that cannot be represented in writing,
• Combines facial gestures and changes in the production of sounds or gestures.
• These are called paralinguistic features.

Spoken Language:

Linguistics

• Linguistics is the study of human language,
• Consists of many components: Characters, words, sentences, etc.
• Human Language is composed of four main building blocks:
• Phonemes,
• Morphemes/Lexemes,
• Syntax, and
• Context/Pragmatics.

Phonemes

• Phonemes are the smallest units of sound in a language,
• They help provide meanings in groups,
• Useful for speech recognition, speech-to-text transcription, and text-to-speech conversion.

Morphemes/Lexemes

• A Morpheme is the smallest unit of language that has a meaning,
• Consist of a combination of phonemes,
• Lexem — derive meaning from related words,
• E.g., run, runs, ran and running are forms of the same lexeme “run.”

Syntax

• The syntax is a set of rules to construct grammatically correct sentences from words and phrases,
• The hierarchical structure of language with words at the bottom, then parts of speech, phrases and finally a sentence,
• Parsing and entity/relation extraction is the NLP task of constructing trees automatically.

Syntax — Phrase structure trees

• Art — A
• N — Test
• Prep — of
• N — Natural Language Processing.

• S -Sentence
• NP — Noun Phrase
• VP — Verb Phrase
• Art — Article
• AP — Adjective Phrase
• N — Noun
• PP — Prepositional Phrase
• Aux — Helping Verb
• P — Prepositon

Context

• Context helps convey a specific meaning,
• Semantics is the direct meaning of words and sentences,
• Pragmatics adds world knowledge, common sense and external context,
• Complex NLP tasks are detecting sarcasm, summarization, and topic modeling.

Sociolinguistics

• Sociolinguistics is the study of language in society,
• It is the interdisciplinary field of sociology and linguistics,
• Language varieties, including dialects and slang,
• Socilolect: Social dialect,
• Idiolect: Collection of varieties that an individual speaks,
• Registers: The way a speaker uses language differently in different circumstances.
• Determined by social occasions, context, purpose, and audience.

Writing Systems

• Alphabets: Phonetic-based writing system that represents consonants and vowels
• E.g., Latin, Cyrillic, Greek
• Abjads: Phonetic-based writing system, mostly consonants and optionally vowels. left to right
• E.g., Arabic, Hebrew
• Abugidas: Each character represents a syllable
• E.g., Devanagari, Thai
• Syllabaries: Phonetic system, different sybols
• E.g., Hiragana, Tsalagi (native american language)
• Logographs: Combination of semantics and phonetics
• E.g., Han Chinese

Encodings

• ASCII: American Standard Code for Information Interchange
• Control characters, some language characters
• 128 Characters max

• Unicode: The Unicode Standard
• A standardized set of character-number mappings maintained by the Unicode Consortium
• UTF-8: Variable width characters