MULTYPO

Multilingual Keyboard-Aware Typo Generator for NLP Robustness

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🚀 Overview

MULTYPO provides realistic, keyboard-based typographical noise across 12+ languages, enabling robust evaluation, stress testing, and synthetic data generation for NLP and LLM systems.

It was originally designed for multilingual robustness research, and is now packaged for public use.

🔥 Key Features

• Multilingual support (English, German, French, Russian, Greek, Arabic, Hindi, Bengali, Tamil, Armenian, Georgian, Hebrew)
• Keyboard-aware typo modeling
  • replace: wrong nearby key
  • insert: accidental double press
  • delete: skipped key
  • transpose: swapped left/right-hand keys
• Horizontal + vertical keyboard neighbors with configurable weights
• Configurable typo distributions
• Built-in excluding sets (numbers, number words, etc.)
• Register custom keyboards and ignoring sets

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📦 Installation

pip install multypo

📝 Quick Start

Generate typos in English

from multypo import generate_typos

text = "This is an example sentence. And here is another one."

noisy = generate_typos(
    text=text,
    language="english",
    typo_rate=0.25,
)

print(noisy)

Example output:

Thi is an ezample sentence. Amd here is anoter one.

🛠️ Advanced Usage: MultiTypoGenerator

from multypo import MultiTypoGenerator

gen = MultiTypoGenerator(
    language="english",
    use_excluding_set=True,
    typo_distribution={"delete":0.2, "insert":0.2, "replace":0.4, "transpose":0.2},
    horizontal_vs_vertical=(2.0, 1.0),
)

typoed = gen.insert_typos_in_text(
    "This is a test sentence. Second sentence here.",
    typo_rate=0.3
)

print(typoed)

🎹 Custom Keyboard Layouts

from multypo import register_keyboard_layout

custom_keyboard = [
    list("qwertyuiop"),
    list("asdfghjkl"),
    list("zxcvbnm"),
]

register_keyboard_layout(
    lang_code="en-custom",
    language="english-custom",
    keyboard_rows=custom_keyboard,
    left_keys=list("qwertasdfgzxcvb"),
    right_keys=list("yuiophjklbnm"),
    ignoring_set={"million", "billion", "42"},
)

Use like any other language:

generate_typos("This is custom.", language="english-custom", typo_rate=0.3)

📏 Adjust Typo Type Probabilities

Set global defaults:

from multypo import set_default_typo_distribution

set_default_typo_distribution({
    "delete": 0.1,
    "insert": 0.2,
    "replace": 0.5,
    "transpose": 0.2,
})

Or override per call:

noisy = generate_typos(
    text="Example",
    language="english",
    typo_rate=0.3,
    typo_distribution={"delete":0.2, "insert":0.2, "replace":0.4, "transpose":0.2},
)

🌍 Supported Languages

from multypo import get_supported_languages

print(get_supported_languages())

Of course, you can always register new languages and their custom keyboard layouts!

📜 License

MIT License.

Citation

@misc{liu2025evaluating,
      title={Evaluating Robustness of Large Language Models Against Multilingual Typographical Errors}, 
      author={Yihong Liu and Raoyuan Zhao and Lena Altinger and Hinrich Schütze and Michael A. Hedderich},
      year={2025},
      eprint={2510.09536},
      archivePrefix={arXiv},
      primaryClass={cs.CL},
      url={https://arxiv.org/abs/2510.09536}, 
}