Implementations in Python and PHP

MLphone

MLphone is a phonetic algorithm for indexing Malayalam words by their pronunciation, like Metaphone for English. The algorithm generates three Romanized phonetic keys (hashes) of varying phonetic affinities for a given Malayalam word.

The algorithm takes into account the context sensitivity of sounds, syntactic and phonetic gemination, compounding, modifiers, and other known exceptions to produce Romanized phonetic hashes of increasing phonetic affinity that are very faithful to the pronunciation of the original Malayalam word.

key0 = a broad phonetic hash comparable to a Metaphone key that doesn't account for hard sounds (ഷ, ണ..) or phonetic modifiers
key1 = is a slightly more inclusive hash that accounts for hard sounds
key2 = highly inclusive and narrow hash that accounts for hard sounds and phonetic modifiers

MLphone was created to aid spelling tolerant Malayalam word search, but may be useful in tasks like spell checking, word suggestion etc.

Examples

Word	key0	key1	key2	Transliteration	Metaphone
നീലക്കുയില്‍	NLKYL	NLKYL	N4LK25Y4L	Neelakkuyil‍	NLKYL
മൃഗം	MRK3	MRK3	MRK3	Mrugam	MRKM
മ്രിഗം	MRK3	MRK3	MRK3	Mrigam	MRKM
ഉത്സവം	U0SV3	U0SV3	U0SV3	Uthsavam	U0SFM
ഉല്‍സവം	U0SV3	U0SV3	U0SV3	Ul‍savam	ULSFM
വാഹനം	VHN3	VHN3	VHN3	Vaahanam	FHNM
വിഹനനം	VHNN3	VHNN3	V4HNN3	Vihananam	FHNNM
രാഷ്ട്രീയം	RSTRY3	RS1TRY3	RS1TR4Y3	Raashtreeyam	RXTRYM
കണ്ണകി	KNK	KNK	KN2K4	Kannaki	KNK
കന്യക	KNYK	KNYK	KNYK	Kanyaka	KNYK
മനം	MN3	MN3	MN3	Manam	MNM
മണം	MN3	MN13	MN13	Manam	MNM
വിഭക്ത്യാഭാസം	VBK0YBS3	VBK0YBS3	V4BK0YBS3	Vibhakthyaabhaasam	FBHK0YBHSM
വലയം	VLY3	VLY3	VLY3	Valayam	FLYM
വളയം	VLY3	VL1Y3	VL1Y3	Valayam	FLYM
രഥം	R03	R03	R03	Ratham	R0M
രദം	R03	R03	R03	Radam	RTM
രത്തം	R03	R03	R03	Rattham	RTM
രധം	R03	R03	R03	Radham	RTHM

Usage

The algorithm's available in Python 3 and PHP.

Python

from mlphone import MLphone

converter = MLphone()
keys = converter.compute(ml_str)

PHP

<?php
	require 'mlphone.php';

	$keys = MLphone::compute($ml_str);
?>

Background

Refer to the Substitution map.

0 denotes the ത group (borrowing from Metaphone where 0 = th)
1 denotes hard sounds (ണ, ള, റ ... as opposed to ന, ല, ര)
2 denotes doubled sounds (ക്ക, ച്ച ...)
3-9 denote modifiers (ം, ി, ു ...)
with the exception of ൃ which is R, and ാ, ഃ, ് that are discarded

Consider the word നീലക്കുയില്‍:

1. Discard all non-Malayalam characters
2. Group modified entitites
	2.1 Group compounds from the compounds table along with their modifiers 	നീല{ക്കു}യില്‍
	2.2 Group non-compounds along with their modifiers 				{നീ}ല{ക്കു}{യി}ല്‍
3. Group unmodified entities
	3.1 Group compounds from the compounds table 					{നീ}{ല}{ക്കു}{യി}{ല്‍}
	3.2 Group non-compounds								{നീ}{ല}{ക്കു}{യി}{ല്‍}
4. Substitute individual modified and un-modified entity groups with corresponding keys {Nീ}{L}{K2ു}{Yി}{L്}
5. Substitute the modifiers in the groups with numeric modifier keys to get key2 	N4LK25Y4L
6. Remove numeric modifiers 2, and 4-9 from key2 to obtain key1 			NLKYL
7. Remove numeric modifiers 1, 2, 4-9 from key2 to obtain key0				NLKYL

Substitution map

Vowels

അA

ആA

ഇI

ഈI

ഉU

ഊU

ഋR

എE

ഏE

ഐAI

ഒO

ഓO

ഔO

Consonants

കK

ഖK

ഗK

ഘK

ങNG

ചC

ഛC

ജJ

ഝJ

ഞNJ

ടT

ഠT

ഡT

ഢT

ണN1

ത0

ഥ0

ദ0

ധ0

നN

പP

ഫF

ബB

ഭB

മM

യY

രR

ലL

വV

ശS1

ഷS1

സS

ഹH

ളL1

ഴZ

റR1

Chills

ൽL

ൾL1

ൺN1

ൻN

ർR1

ൿK

Compounds

ക്കK2

ഗ്ഗK

ങ്ങNG

ച്ചC2

ജ്ജJ

ഞ്ഞNJ

ട്ടT2

ണ്ണN2

ത്ത0

ദ്ദD

ദ്ധD

ന്നNN

ന്തN0

ങ്കNK

ണ്ടN1T

ബ്ബB

പ്പP2

മ്മM2

യ്യY

ല്ലL2

വ്വV

ശ്ശS1

സ്സS

ള്ളL12

ഞ്ചNC

ക്ഷKS1

മ്പMP

റ്റT

ന്റNT