avro-phonetic-go: Avro-style Banglish to বাংলা transliteration in Go

Source: Dev.to

If you work with Bengali users, you already know the problem.

People type Bangla using Latin letters. Not carefully. Not consistently. Yet they expect your application to understand them.

The Avro Phonetic keyboard showed that this problem can be solved using a grammar‑driven approach: pattern matching combined with local context rules.

This article introduces avro-phonetic-go, a Go library that implements an Avro‑style phonetic transliteration engine with a clean, production‑oriented API.

Design goals

The library was built with the following principles:

• Grammar‑driven, not hardcoded
• Deterministic output using longest‑match scanning
• Explicit rule evaluation (prefix and suffix constraints)
• No magic heuristics in strict mode
• Optional BD mode for modern Bangladeshi typing shortcuts

The overall idea is credited to the Avro Phonetic keyboard. The internal design was strongly influenced by the PHP reference implementation: .

Quick example

Strict mode

fmt.Println(avrophonetic.To("ami bangla gan gai"))
// আমি বাংলা গান গাই

BD mode (opt‑in)

fmt.Println(avrophonetic.ToBD("tmi valo"))
// তুমি ভালো

How it works

At a high level, the engine works in four steps:

1. Load a grammar consisting of patterns and rules
2. Build a trie for fast longest‑match lookup
3. Scan the input left to right
4. Validate candidate patterns using local context rules

Rules are evaluated only against immediate neighbors. There is no backtracking, which keeps the algorithm predictable and fast.

Strict mode vs BD mode

• Strict mode behaves as a clean Avro‑style baseline. Use it when you need exact Avro behavior.
• BD mode layers a small set of additional patterns on top of the strict grammar, capturing real‑world Bangladeshi typing habits without polluting the base grammar.

This separation keeps the engine usable for both compatibility‑focused and user‑experience‑oriented applications.

Custom grammar support

The engine is fully grammar‑driven. You can load a complete grammar JSON file to reach parity with any grammar you prefer:

g, _ := avrophonetic.FromGrammarFile("grammar.json")
a := avrophonetic.New(avrophonetic.WithGrammar(g))
fmt.Println(a.Parse("ami"))

This makes the library suitable for search indexing, chat processing, form normalization, and NLP pipelines.

Credits

• Avro Phonetic keyboard: original idea and grammar concept
• PHP reference implementation:

This project is an independent Go implementation and is not affiliated with the original Avro project.

Closing thoughts

Transliteration is a small feature with outsized impact. If your product handles Bengali user input, doing this well is no longer optional.

Repository:
Documentation and examples are available in the README.