---
title: "FreeLing 3.0: Towards Wider Multilinguality — Padró 2012"
description: "FreeLing is an open-source C++ library that gives NLP application developers ready-made language analyzers, so they do not have to build basic processing…"
authors: ["Lluís Padró", "Evgeny Stanilovsky"]
year: 2012
venue: "Proceedings of the Eighth International Conference on Language Resources and Evaluation (LREC'12)"
source: "https://aclanthology.org/L12-1224/"
licence: "CC BY-NC 4.0 (ELRA, LREC proceedings)"
licence_url: "https://creativecommons.org/licenses/by-nc/4.0/"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/en/papers/padro-2012-freeling-3-0-wider-multilinguality/"
---
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# FreeLing 3.0: Towards Wider Multilinguality

**Authors:** [Lluís Padró](https://md.research.elamur.ai/free/en/authors/lluis-padro/), Evgeny Stanilovsky · **Year:** 2012 · **Venue:** Proceedings of the Eighth International Conference on Language Resources and Evaluation (LREC'12) · **Licence:** [CC BY-NC 4.0 (ELRA, LREC proceedings)](https://creativecommons.org/licenses/by-nc/4.0/)

**Links:** [Publisher's page](https://aclanthology.org/L12-1224/) · [PDF](https://aclanthology.org/L12-1224.pdf) · [OpenAlex](https://openalex.org/W66137051)

**Citations:** 489 citations (openalex-snapshot · 2026-10-14) · [121](#cited-by) in our library, of the 140673 papers whose bibliographies we read

## Summary
FreeLing is an open-source C++ library that gives NLP application developers ready-made language analyzers, so they do not have to build basic processing from scratch. This paper describes version 3.0 and its design. The library has two layers: linguistic service modules and the client applications that call them. It uses data classes (analysis, word, sentence, paragraph, document) and processing classes that mostly share one `processor` interface. The pipeline runs from tokenization and morphology through PoS tagging, NER, sense annotation with UKB, chunk and rule-based dependency parsing, and co-reference. The main change in 3.0 is full UTF8 support. This made a language identifier possible, allows locale-aware POSIX regular expressions, and opened the way to non-Latin scripts such as Russian. Other additions include user-defined regex tagging, forbidden trigrams in the HMM tagger, SAMPA phonetic encoding, and configurable sense-repository mapping. The library is already used in several commercial products. Its value lies in giving a growing multilingual community a reusable, robust, industry-ready foundation for analysis.

## Key points
- **Licensing and adoption:**
  - FreeLing is distributed under GPL and dual-licensed for commercial embedding. The first release was in 2003.
  - Version 2.2 was downloaded over 88,000 times after its September 2010 release.
  - The 3.0 alpha source was downloaded 530 times in its first five weeks.
- **Languages:**
  - Coverage grew from English, Spanish and Catalan to nine languages: Galician, Italian, Welsh, Portuguese, Asturian and Russian were added.
  - There is also a diachronic Spanish variant covering the 12th–16th centuries. It was applied in a study of how the verb *haber* evolved.
- **Accuracy figures:**
  - The PoS taggers reach roughly 97–98%. There are two of them: an HMM tagger following Brants (2000) and a relaxation-labelling tagger that can combine statistics with hand-written rules.
  - The capitalization-based NE detector is close to 90% accurate. The slower recognizer based on the CoNLL-2002 winning system exceeds 94%.
- **Reused components:** word sense disambiguation comes directly from UKB, and co-reference follows Soon et al. (2001).
- **Industrial users:** Ruby Reader, Vi-Clone, TextToSign, Dixio and Aport News (Russian news clustering).
- **Planned work:** a spelling-correction module, thread-based processors, and FOMA to replace the language-specific C++ recognizers for dates, numbers and quantities.

## Interesting ideas
- **Shared processor interface:** nearly every module enriches a sentence either in place or as a copy, using the same method signature. Modules can therefore be chained, swapped or called individually, which suits any modular pipeline, including one for Ukrainian.
- **Regex escape hatch for domain tokens:** a user map applies a regex and assigns a fixed lemma/PoS. For example, Twitter handles can be tagged as proper nouns without retraining NER. This is a cheap way to adapt a pipeline to new domains such as social media or trade documents.
- **Forbidden trigrams:** the tagger model lists tag sequences that are linguistically impossible and keeps them out of smoothing, so their probability stays at zero. This injects linguistic knowledge into a statistical model and could transfer to other smoothed sequence models.
- **Locale-aware character classes:** writing tokenizer rules with POSIX classes such as `[[:alpha:]]` instead of hard-coded alphabets makes one rule work across scripts. This is valuable when processing Cyrillic and Latin text in the same system.
- **Declarative PoS mapping to the sense inventory:** a configurable mapping bridges the tagset to WordNet categories and can also look up the surface form. For example, *falling* can receive adjective senses as well as verb senses. A similar mapping layer could connect a Ukrainian tagset to external lexical resources.

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

Fields: [Linguistics & languages](https://md.research.elamur.ai/free/en/shelves/linguistics/)

Topics: [Part-of-speech tagging](https://md.research.elamur.ai/free/en/topics/part-of-speech-tagging/)

## Cited by

Cited by

121 papers of our library cite it (of the 140673 whose bibliographies we read); 1 of them have a page here, 120 not yet.

- [Findings of the 2015 Workshop on Statistical Machine Translation](https://md.research.elamur.ai/free/en/papers/bojar-2015-findings-2015-workshop-statistical-machine/)

## Cite

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

```bibtex
@inproceedings{padro2012freeling,
  title = {{FreeLing 3.0: Towards Wider Multilinguality}},
  author = {Padró, Lluís and Stanilovsky, Evgeny},
  booktitle = {Proceedings of the Eighth International Conference on Language Resources and Evaluation (LREC'12)},
  year = {2012},
  doi = {10.63317/4etcsxkc5akn},
  url = {https://doi.org/10.63317/4etcsxkc5akn}
}
```

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## References

12 references, 2 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet.

1. Eneko Agirre and Aitor Soroa. 2009. Personalizing pagerank for word sense disambiguation. In Proceedings of the 12th conference of the European chapter of the Association for Computational Linguistics (EACL-2009), Athens, Greece. [find](https://scholar.google.com/scholar?q=Eneko+Agirre+and+Aitor+Soroa%2E+2009%2E+Personalizing+pagerank+for+word+sense+disambiguation%2E+In+Proceedings+of+the+12th+conference+of+the+European+chapter+of+the+Association+for+Computational+Linguistics)
2. Jordi Atserias and Horacio Rodrı́guez. 1998. Tacat: Tagged corpus analizer tool. Technical report lsi-98-2-t, Departament de LSI. Universitat Politècnica de Catalunya. [find](https://scholar.google.com/scholar?q=Jordi+Atserias+and+Horacio+Rodr%C4%B1%CC%81guez%2E+1998%2E+Tacat%3A+Tagged+corpus+analizer+tool%2E+Technical+report+lsi%2D98%2D2%2Dt%2C+Departament+de+LSI%2E+Universitat+Polite%CC%80cnica+de+Catalunya%2E)
3. Jordi Atserias, Elisabet Comelles, and Aingeru Mayor. 2005. Txala un analizador libre de dependencias para el castellano. Procesamiento del Lenguaje Natural, (35):455–456, September. [find](https://scholar.google.com/scholar?q=Jordi+Atserias%2C+Elisabet+Comelles%2C+and+Aingeru+Mayor%2E+2005%2E+Txala+un+analizador+libre+de+dependencias+para+el+castellano%2E+Procesamiento+del+Lenguaje+Natural%2C+%2835%29%3A455%E2%80%93456%2C+September%2E)
4. Thorsten Brants. 2000. Tnt - a statistical part- of-speech tagger. In Proceedings of the 6th Conference on Applied Natural Language Processing, ANLP. ACL. [find](https://scholar.google.com/scholar?q=Thorsten+Brants%2E+2000%2E+Tnt+%2D+a+statistical+part%2D+of%2Dspeech+tagger%2E+In+Proceedings+of+the+6th+Conference+on+Applied+Natural+Language+Processing%2C+ANLP%2E+ACL%2E) [our card](https://md.research.elamur.ai/free/en/papers/brants-2000-tnt-statistical-part-speech-tagger/)
5. Xavier Carreras, Lluı́s Màrquez, and Lluı́s Padró. 2002. Named entity extraction using adaboost. In Proceedings of CoNLL Shared Task, pages 167–170, Taipei, Taiwan. [find](https://scholar.google.com/scholar?q=Xavier+Carreras%2C+Llu%C4%B1%CC%81s+Ma%CC%80rquez%2C+and+Llu%C4%B1%CC%81s+Padro%CC%81%2E+2002%2E+Named+entity+extraction+using+adaboost%2E+In+Proceedings+of+CoNLL+Shared+Task%2C+pages+167%E2%80%93170%2C+Taipei%2C+Taiwan%2E)
6. C.C. Chang and C.J. Lin. 2011. Libsvm : a library for support vector machines. ACM Transactions on Intelligent Systems and Technology, 2(3):1–27, April. [find](https://scholar.google.com/scholar?q=C%2EC%2E+Chang+and+C%2EJ%2E+Lin%2E+2011%2E+Libsvm+%3A+a+library+for+support+vector+machines%2E+ACM+Transactions+on+Intelligent+Systems+and+Technology%2C+2%283%29%3A1%E2%80%9327%2C+April%2E)
7. Muntsa Padró and Lluı́s Padró. 2004. Comparing methods for language identification. Procesamiento del Lenguaje Natural, (33):155–162, September. [find](https://scholar.google.com/scholar?q=Muntsa+Padro%CC%81+and+Llu%C4%B1%CC%81s+Padro%CC%81%2E+2004%2E+Comparing+methods+for+language+identification%2E+Procesamiento+del+Lenguaje+Natural%2C+%2833%29%3A155%E2%80%93162%2C+September%2E)
8. Lluı́s Padró. 1998. A Hybrid Environment for Syntax– Semantic Tagging. Ph.D. thesis, Dep. Llenguatges i Sistemes Informàtics. Universitat Politècnica de Catalunya, February. [http://www.lsi.upc.es/˜padro](http://www.lsi.upc.es/˜padro). [↗](http://www.lsi.upc.es/˜padro)
9. W.M. Soon, H. T. Ng, and D.C.Y. Lim. 2001. A machine learning approach to coreference resolution of noun phrases. Computational Linguistics, 27(4):521– 544. [find](https://scholar.google.com/scholar?q=W%2EM%2E+Soon%2C+H%2E+T%2E+Ng%2C+and+D%2EC%2EY%2E+Lim%2E+2001%2E+A+machine+learning+approach+to+coreference+resolution+of+noun+phrases%2E+Computational+Linguistics%2C+27%284%29%3A521%E2%80%93+544%2E) [our card](https://md.research.elamur.ai/free/en/papers/soon-2001-machine-learning-approach-coreference-resolution/)
10. Cristina Sánchez-Marco and Stefan Evert. 2011. Measuring semantic change: The case of spanish participial constructions. In Proceedings of 4th Conference on Quantitative Investigations in Theoretical Linguistics (QITL-4), Berlin, Germany, March. [find](https://scholar.google.com/scholar?q=Cristina+Sa%CC%81nchez%2DMarco+and+Stefan+Evert%2E+2011%2E+Measuring+semantic+change%3A+The+case+of+spanish+participial+constructions%2E+In+Proceedings+of+4th+Conference+on+Quantitative+Investigations+in+Theoretical)
11. Cristina Sánchez-Marco, Gemma Boleda, and Lluı́s Padró. 2011. Extending the tool, or how to annotate historical language varieties. In Proceedings of the 5th ACL-HLT Workshop on Language Technology for Cultural Heritage, Social Sciences, and Humanities, pages 1–9, Portland, OR, USA, June. Associat… [find](https://scholar.google.com/scholar?q=Cristina+Sa%CC%81nchez%2DMarco%2C+Gemma+Boleda%2C+and+Llu%C4%B1%CC%81s+Padro%CC%81%2E+2011%2E+Extending+the+tool%2C+or+how+to+annotate+historical+language+varieties%2E+In+Proceedings+of+the+5th+ACL%2DHLT+Workshop+on+Language+Technology+)
12. Cristina Sánchez-Marco. 2012. Tracing the development of Spanish participial constructions: An empirical study of language change. Ph.D. thesis, Universitat Pompeu Fabra, Barcelona, Spain. (forthcoming). [find](https://scholar.google.com/scholar?q=Cristina+Sa%CC%81nchez%2DMarco%2E+2012%2E+Tracing+the+development+of+Spanish+participial+constructions%3A+An+empirical+study+of+language+change%2E+Ph%2ED%2E+thesis%2C+Universitat+Pompeu+Fabra%2C+Barcelona%2C+Spain%2E+%28forthcomi)