Vocab has been launched on the BBC's Cymru'r Byd website

Vocab lets users hold the cursor over a word and get an instant translation without having to leave the site.

Developed by BBC Wales' New Media department, the programme is available free of charge to Welsh-language websites outside the BBC.

Vocab became available on BBC Wales' Cymru'r Byd website on Tuesday.

The device uses a database of 22,000 words chosen from the BBC's Learn Welsh online dictionary.

Vocab offers translations of 22,000 words

It is aimed at everyone from Welsh learners to fluent Welsh-speakers confronted with an unfamiliar word.

Vocab allows a word's meaning to be checked instantly without a reader having to use either a paper dictionary or click out of the site to a separate online dictionary.

Grahame Davies, executive producer of Welsh language New Media at BBC Wales, said: "We tested the system at this year's National Eisteddfod in Newport and we received fantastic feedback from a wide range of people with diverse Welsh-language reading skills."

Other Welsh-language websites will be able to take advantage of the programme free of charge.

Mr Davies said: "In conjunction with the Welsh Language Board, BBC Wales has taken the decision to share the benefits with all Welsh-language websites by offering the programme as open source code."

A new version of the programme will be made available, developed with the Welsh Language Board and the Department of Applied Linguistics at the University of Wales, Swansea, which allows users to select different levels of help according to their reading ability in Welsh.

The programme can be switched on or off

The vocabulary currently used is based on a dictionary developed at the University College of Wales, Bangor.

The developers of Vocab also believe the programme can be used on websites in different languages across the world.

"It has been designed so that it can be used to translate words from any language into any other language," said Mr Davies.

"We have already investigated the possibility of a Welsh-Spanish Vocab aimed at the Welsh community in Patagonia and we can see the potential popularity of versions linking English with many other languages spoken in the UK.

"Imagine how difficult it is for someone for whom English is a second language to fill in some official forms online when they are faced with terms such as 'superannuation' or 'mortgagor'.

"An English-Urdu version of Vocab could enable such sites to be accessible to thousands more people in the UK."