GF Offline Translator - a mobile speech and text translation app for Android and iOS

Android: download for free from Play Store! Or take the current development version.
iOS (iPhone, iPad): coming in June 2015.

Or try first a web version of the translator

GF Offline Translator is based on grammar and semantics. It is compact in size and gives control on quality. Its technology is inspired by compilers, which are programs that translate computer languages. Most other translators for human language are based on statistics and have less control of quality and are much bigger, so that they require either an internet connection or a huge storage on your phone.

The app indicates translation confidence with colours: The green translations come from a tourist phrasebook, which allows you to translate things like "hello" and "how far is the airport from the hotel".

You can translate both speech and text, as selected in the menu in the upper right corner. Both kinds of input can be edited with the keyboard by first tapping at the input field. This is often needed because of speech recognition errors. Changing words from upper to lower case may also be needed. At the moment, Japanese and Thai input must be separated to words, whereas Chinese works without spaces.

Translation works between any of the 14 supported languages, which means 182 language pairs in the current development version (the official Android version has 12 languages). But different languages are on different levels of development. The following table gives a rough idea of what to expect:

coverage quality speed speech
Bulgarian in only
Catalan in only
Finnish in only
Hindi in only
Swedish in only

The speech input and output use Google's voice services. Their status can hence change without notice. You can make it more stable by installing third-party speech tools, such as SVOX, which provides output for most of the listed languages.

When you tap on a translation you get a screen with alternative translations. Tapping on each of the alternatives gives you grammatical information: an inflection table, if it is a single word, and a syntax tree otherwise.

Powered by GF, built by support from the GF community and from Digital Grammars.

Publication: EACL 2014 demo paper