---
title: "A Compression Technique for Arabic Dictionaries: The Affix"
description: "This paper addresses how to keep a dictionary for non-diacritical (unvowelled) Arabic small enough for automatic… Cited by 1 paper here."
authors: ["Ben Hamadou, Abdelmajid"]
year: 1986
venue: "Coling 1986 Volume 1: The 11th International Conference on Computational Linguistics"
source: "https://aclanthology.org/C86-1068/"
licence: "CC BY-NC-SA 3.0 (ACL Anthology, before 2016)"
licence_url: "https://creativecommons.org/licenses/by-nc-sa/3.0/"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/en/papers/hamadou-1986-compression-technique-arabic-dictionaries-affix/"
---
[Elamur Research](https://md.research.elamur.ai/free/en/) · [this page in HTML](https://research.elamur.ai/free/en/papers/hamadou-1986-compression-technique-arabic-dictionaries-affix/)

[home](https://md.research.elamur.ai/free/en/) / [papers](https://md.research.elamur.ai/free/en/papers/) / [1986](https://md.research.elamur.ai/free/en/papers/1986/) / A Compression Technique for Arabic Dictionaries: The Affix Analysis

# A Compression Technique for Arabic Dictionaries: The Affix Analysis

**Authors:** Ben Hamadou, Abdelmajid · **Year:** 1986 · **Venue:** [Coling 1986 Volume 1: The 11th International Conference on Computational Linguistics](https://md.research.elamur.ai/free/en/venues/coling/) ([COLING 1986](https://md.research.elamur.ai/free/en/venues/coling/1986/)) · **Licence:** [CC BY-NC-SA 3.0 (ACL Anthology, before 2016)](https://creativecommons.org/licenses/by-nc-sa/3.0/)

**Links:** [Publisher's page](https://aclanthology.org/C86-1068/) · [PDF](https://aclanthology.org/C86-1068.pdf)

**Citations:** 1 in our library, of the 149,439 papers whose bibliographies we read

## Summary
This paper addresses how to keep a dictionary for non-diacritical (unvowelled) Arabic small enough for automatic processing. The work comes from a project on detecting and correcting spelling errors. Rather than listing every word form, the author stores only roots, the non-redundant part of the language. Prefixes, infixes and suffixes are recovered by morphological analysis.

A decomposition module strips candidate prefixes and suffixes using lookup tables. A single analyser then identifies the infix in the remaining string. The analysis accounts for transformations that alter surface forms, mainly in roots containing yaa, waw or hamza. A validation module filters candidate decompositions by checking affix compatibility at three levels and by consulting the root dictionary.

The dictionary was built from a functional-Arabic corpus of the Maghreb countries and holds about 1,600 roots. The method was tested on roughly 100,000 words. It matters because it exploits Arabic's derivational root-and-pattern structure. A compact, memory-resident lexicon then covers many forms, and the segmentation it produces helps spelling correction.

## Key points
- The paper compares three ways to shrink a dictionary:
  - sharing common prefixes in chained lists, as in the PIAF system;
  - topic-specific dictionaries layered over a base dictionary;
  - affix analysis, which is the approach used in DECIO-SPELL and the one the author adopts.
- Surface changes are split into two kinds:
  - morpho-phonological substitutions, which keep word length;
  - purely phonological deletions, which shorten the word.
- The prefix–suffix congruity matrix has 609 cells (21 prefixes × 29 suffixes). Each cell is 0 if the pair is incompatible, or an index N_k (1–226) pointing to a list of allowed Morphological Codes. The code produced for the infix is intersected with that list.
- The root dictionary has about 1,500 three-letter roots and 100 four-letter roots, drawn from the corpus of the Permanent Commission of Functional Arabic (PCFA 76). Each root is accessed directly by a key computed from its first three letters and its length.
- The system was implemented in FORTRAN and tested on about 100,000 words. For checking whether a word exists, the first valid decomposition is enough.

## Interesting ideas
- Validation is factored into a small prefix×suffix matrix whose cells point to shared lists of permitted pattern codes, so legality checks become cheap set intersections instead of a large enumerated table.
- Decomposition runs in two stages: outer affixes are peeled off via tables, then one generic analyser handles the internal change, so a single mechanism covers all patterns.
- Spelling transformations are classed as length-preserving substitutions versus length-changing deletions, which tells the reverse analyser what kinds of edits to undo.
- The root lexicon itself records which non-systematic patterns each root legitimately takes, treating some impossible forms as lexical or semantic gaps rather than morphological ones.
- A word is stored as a root plus pattern codes instead of a full string, which both compresses the lexicon and yields a natural segmentation useful for correction.

## For Mova

How these ideas could serve Mova, our small open language model — its files, stages and tests:

- **I1** (tokens): English affix stacking (un-…-able-ness) could be validated the same way, with a compact compatibility table pointing to allowed morphological codes in the en lemmatizer.
- **I2** (tokens): irregular stem changes (sing/sang, mouse/mice) could be handled by one analyser applied after suffix stripping, keeping the morphology code uniform and each step explainable.
- **I3** (tokens): tagging English orthographic rules (y→i, e-deletion, consonant doubling) by this distinction would make lemma recovery rules easier to organise and trace.
- **I4** (world): verb-class knowledge could mark, per lemma, which derivations or alternations are attested, so the system can reject plausible-looking but unused forms.
- **I5** (back): the text → graph → text compressor could encode words as lemma plus morphological features and regenerate surface forms, saving space while staying fully reversible.

*Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.*

📚 Shelves (2): [🖥️ Computer Science](https://md.research.elamur.ai/free/en/shelves/computer-science/) · 18,614 works · [🤖 Artificial Intelligence](https://md.research.elamur.ai/free/en/shelves/computer-science/artificial-intelligence/) · 17,965 works

🧭 Topics (2): [Semitic languages](https://md.research.elamur.ai/free/en/topics/semitic-languages/) · 3,066 works · [🪶 Efficient models & compression](https://md.research.elamur.ai/free/en/topics/efficient-models/) · 297 works

## Cite

Cite as: Ben Hamadou, Abdelmajid. 1986. A Compression Technique for Arabic Dictionaries: The Affix Analysis. Coling 1986 Volume 1: The 11th International Conference on Computational Linguistics.

The paper itself, not this page. BibTeX from the library's record of the work.

```bibtex
@inproceedings{abdelmajid1986compression,
  title = {{A Compression Technique for Arabic Dictionaries: The Affix Analysis}},
  author = {Ben Hamadou, Abdelmajid},
  booktitle = {Coling 1986 Volume 1: The 11th International Conference on Computational Linguistics},
  year = {1986},
  url = {https://aclanthology.org/C86-1068/}
}
```

- [← previous A Compositional Approach to the Translation of Temporal Expressions in the Rosetta System](https://md.research.elamur.ai/free/en/papers/appelo-1986-compositional-approach-translation-temporal-expressions/)
- [next → A New Predictive Analyzer of English](https://md.research.elamur.ai/free/en/papers/musha-1986-new-predictive-analyzer-english/)
- [↑ back to papers of 1986](https://md.research.elamur.ai/free/en/papers/1986/)

*Updated 31 October 2026*