Tamil Spell Checker

Idea for building simple Tamil Spell Checker came from a conversation with T Shrinivasan from open-tamil team.

Tamil Spell Checker uses below approach to suggest different spellings for a word

• Check whether it is a valid Tamil word using Bloom Filter
• Use Levenstein Distance (edit distance of 2) to suggest words when it is not a tamil word

Project Madurai Crawler

Project Madurai has good collection of tamil works. Use Project Madurai Crawler to generate Tamil unique word list.

To run it use the below command

python ProjectMaduraiCrawler.py

Create Bloom Filter File

Bloom Filter is a space efficient and compute optimized probablistic datastructure designed to tell whether an item is present in a set or not. More information on Bloom Filter can be found in wiki.

• Spellchecker is using Bloom Filter to check whether a word is a valid tamil word or not.
• Bloom Filter Datastructure file has to be created first before using to check validity of a word

To generate Bloom Filter file use the below command

python TamilBloomFilterCreator.py

Sample code to check whether a word is valid tamil word

from TamilwordChecker import TamilwordChecker
unique_word_count = 2043478
tamilwordchecker = TamilwordChecker(unique_word_count,"tamil_bloom_filter.txt")
print(tamilwordchecker.tamil_word_exists("மேகம்"))

Sample code to check get spell check corrections

from TamilSpellingAutoCorrect import TamilSpellingAutoCorrect
spellchecker  = TamilSpellingAutoCorrect("tamil_bloom_filter.txt","tamilwordlist.txt")
from_spell_checker_list = spellchecker.tamil_correct_spelling("மேக்ம்")
print(from_spell_checker_list)

Norvig Algorithm

Norvig algorithm can run faster than exhaustive search method; you can use it as follows,

from tamilspellchecker.TamilSpellingAutoCorrect import TamilSpellingAutoCorrect, get_data
from pprint import pprint
from tamil.utf8 import get_letters
spellchecker = TamilSpellingAutoCorrect(get_data("tamil_bloom_filter.txt"), get_data("tamilwordlist.txt"))
results = spellchecker.tamil_Norvig_correct_spelling("தமிழ்னாடு") #தமிழ்நாடு என்பது சரியான சொல்.
results = list(filter(lambda x: len(get_letters(x)) >= 4,results )) #filter for words >= 4 letters
results = list(filter(lambda x: len(get_letters(x)) <= 6,results )) #and for words <= 6 letters
pprint(results)
assert 'தமிழ்நாடு' in results

Accuracy Issues

Accuracy of Tamilwordchecker depends on the list of unique words that is there in tamilwordlist.txt. Need to add more unique words from other sources.