What is Apertium?

Apertium is an open-source machine translation platform, initially aimed at related-language pairs but recently expanded to deal with more divergent language pairs (such as English-Catalan). The platform provides

1. a language-independent machine translation engine
2. tools to manage the linguistic data necessary to build a machine translation system for a given language pair and
3. linguistic data for a growing number of language pairs.

Apertium uses a shallow-transfer machine translation engine which processes the input text in stages, as in an assembly line: de-formatting, morphological analysis, part-of-speech disambiguation, shallow structural transfer, lexical transfer, morphological generation, and re-formatting.

Apertium uses finite-state transducers for all lexical processing operations (morphological analysis and generation, lexical transfer), hidden Markov models for part-of-speech tagging, and multi-stage finite-state based chunking for structural transfer.

The initial design was largely based upon that of systems already developed by the Transducens group at the Universitat d'Alacant, such as interNOSTRUM (Spanish-Catalan, and Traductor Universia (Spanish-Portuguese).

It is possible to use Apertium to build machine translation systems for a variety of language pairs; to that end, Apertium uses simple XML-based standard formats to encode the linguistic data needed (either by hand or by converting existing data), which are compiled using the provided tools into the high-speed formats used by the engine.