Soundex

The Soundex class provides a phonetic hash code for Portuguese words, similar to the classic Soundex algorithm but adapted for Brazilian Portuguese. It generates a 4-character code that represents the phonetic sound of a word.

Basic Usage

use ByJG\WordProcess\Portuguese\Soundex;

echo Soundex::process('brasília'); // Output: B625
echo Soundex::process('brazilia'); // Output: B625
echo Soundex::process('brasil');   // Output: B625

All three variations produce the same Soundex code, making them easily groupable as phonetically similar words.

tip

Soundex is particularly useful for indexing and searching when you need to group phonetically similar words together.

How It Works

The Soundex algorithm:

1. Applies Metaphone first: Converts the word to its phonetic representation
2. Keeps the first letter: Preserves the initial character
3. Maps consonants to digits: Converts similar-sounding consonants to the same number
4. Generates 4-character code: Creates a fixed-length code for comparison

Consonant Mapping

The algorithm maps consonants to digits based on their phonetic similarity:

Digit	Consonants
1	B, F, P, V
2	C, G, J, K, Q, S, X, Z
3	D, T
4	L
5	M, N
6	R

Examples

Brand Names

Different spellings of brand names generate the same Soundex code:

echo Soundex::process('nike');    // Output: N200
echo Soundex::process('niky');    // Output: N200
echo Soundex::process('niki');    // Output: N200
echo Soundex::process('nyke');    // Output: N200
echo Soundex::process('naique'); // Output: N200

Common Words

Words with similar pronunciation share the same code:

// Fruit variations
echo Soundex::process('melancia');  // Output: M452
echo Soundex::process('melansia');  // Output: M452
echo Soundex::process('melanssia'); // Output: M452

// Name variations
echo Soundex::process('Michael');   // Output: M240
echo Soundex::process('Maichael');  // Output: M240
echo Soundex::process('Mychael');   // Output: M240

Real-World Examples

// Family names
echo Soundex::process('Jackson');   // Output: J250
echo Soundex::process('Jacksom');   // Output: J250
echo Soundex::process('Jeckson');   // Output: J250

// Color variations
echo Soundex::process('marrom');    // Output: M650
echo Soundex::process('marron');    // Output: M650
echo Soundex::process('maron');     // Output: M650
echo Soundex::process('marom');     // Output: M650

// Places
echo Soundex::process('wellington'); // Output: U453
echo Soundex::process('uelintom');   // Output: U453

// Common words
echo Soundex::process('casa');      // Output: K200
echo Soundex::process('caça');      // Output: K200
echo Soundex::process('caçar');     // Output: K200

Method Reference

process(string $text): string

Generates a Soundex code for the given Portuguese text.

Parameters:

• $text (string): The text to process

Returns:

• (string): A 4-character Soundex code (1 letter + 3 digits, padded with zeros if needed)

Example:

$code = Soundex::process('casa');
echo $code; // Output: K200

Comparison: Soundex vs Metaphone

Feature	Soundex	Metaphone
Output	Fixed 4-character code	Variable-length phonetic representation
Use case	Grouping similar words	Full-text approximate search
Precision	Less precise, groups more broadly	More precise, maintains more detail
Database indexing	Ideal for indexed columns	Better for full-text search

When to use Soundex

• Duplicate detection: Finding potential duplicates in databases
• Name matching: Matching names with different spellings
• Grouping: Organizing similar-sounding items together
• Indexed searches: When you need fast lookups with database indexes

When to use Metaphone

• Full-text search: When you need to search entire phrases or sentences
• Detailed matching: When you need more precision in phonetic matching
• Display purposes: When you want to show the phonetic representation
• Custom rules: When you need to understand or modify the transformation rules