NLPLanguageIdentification.swift

import UIKit

let inputString = "Delhi, India’s capital territory, is a massive metropolitan area in the country’s north. In Old Delhi, a neighborhood dating to the 1600s, stands the imposing Mughal-era Red Fort, a symbol of India, and the sprawling Jama Masjid mosque, whose courtyard accommodates 25,000 people. Nearby is Chandni Chowk, a vibrant bazaar filled with food carts, sweets shops and spice stalls."


// tag schemes: tag schemes are constants that are used to identify pieces of information that we want from the input text. Tag schemes asks tagger to look for informations like
// Token type: a contant to classify each character as a word, punctuation or a whitespace
// Language: a constant to determine langugage of the token
// LexicalClass: this constant determines class of each token. i.e. it determines part of speech for a word, type of punctuation for a punctuation or type of whitespace for a whitespace
// Name type: this constant looks for tokens that are part of a named entity. It will look for a person's name , organizational name and name of a place
// Lemma: this constant returns the stem of word.
let tagger = NSLinguisticTagger(tagSchemes: [NSLinguisticTagScheme.tokenType, .language, .lexicalClass, .nameType, .lemma], options: 0)

// Options are the way to tell API as how to split the text. We are asking to ignore any punctuations and any whitespaces. Also, if there is a named entity then join it together i.e instead of considering "New" "Delhi" as two entities, join them together as one which is "New Delhi"

let options: NSLinguisticTagger.Options = [NSLinguisticTagger.Options.omitPunctuation, .omitWhitespace, .joinNames]

// ******************************************
// Language identification
// here we will give input string to the tagger and ask the dominant language in the string.
// Dominant language is the most frequently occurring language in the string so if our string had mix of english, hindi, spanish and french words then it would choose the most common language

func languageIdentification() {
    tagger.string = inputString
    print(tagger.dominantLanguage!)
}

languageIdentification()