Despite a name that still exudes 1960s sci-fi silliness, the Klingons have spawned what many of Star Trek's more hard-core fans consider should be the new international language of choice.

In the original series, in the days before Klingons had ridges on their brows and the Enterprise's universal translator never malfunctioned, they spoke perfect English. But for their return in 1979's 'Star Trek: the Motion Picture', subtitles were employed for the first time.

This basic Klingon language was made up of a few random words invented by James Doohan (Scotty), an actor with a keen interest in linguistics and accents, if not a natural gift for them. Klingon was immediately distinguished by its extremely curt - 'Chrkt!' - and guttural phrasing, single words apparently translating as relatively long, complex sentences.

But it was not until Paramount saw the story outline for 'Star Trek III: The Search for Spock' five years later that Klingon as a language was truly legitimised. The film featured Christopher Lloyd in a frenetic performance as the Klingon Commander Kruge, and much aggressive banter between Lloyd's character and his taciturn crew. Paramount hired linguist and Star Trek fan Marc Orkrand to create an entire Klingon vocabulary for the exchanges, a labour of love now on sale as 'The Klingon Dictionary'.

The introduction of Lieutenant Worf as a regular character in The Next Generation led to a dramatic deepening of the Klingon's cultural back-story and with it the expansion of the Klingon dialect.

'The Klingon Dictionary', which has sold a quarter of a million copies to date, has now been joined by 'Conversational Klingon' and 'Power Klingon'. There is also an ongoing attempt among one fan faction to produce a version of the Bible in Klingon, so far unsuccessfully. It is rumoured the world's fluent speakers of Klingon remain in a small minority, although converts have been known to claim that 'Klingon is the new Esperanto.'