Nothing illustrates Luxembourg's determined struggle for a national identity as clearly as the little-known mother tongue. Long accustomed to invasion and occupation, the population has traditionally retreated behind the linguistic ramparts of a language called Luxembourgish, or Letzebuergesch. The language constantly bemuses visitors. Streets and shops have French names. So do menus in restaurants. Yet the population speaks in a different tongue. Justice is dispensed in the courts almost exclusively in French but witnesses invariably speak Luxembourgish. For legal documents, French or German are the only authorised languages. In a largely Catholic country, the Catholic church uses German in written communications - but sermons and even the liturgy are again spoken in the native tongue (although it is rare to hear the scriptures translated into Luxembourgish). Priests frequently speak in French. The publication of state laws, meanwhile, has alternated between French and German at least seven times over the past two centuries. Even in schools, the conundrum is no less confusing. At the age of six, Luxembourg children learn to read and write in German. At seven, they begin to study the lingua franca of education, French. At home, they speak Luxembourgish. The media is a similar cocktail of all three languages. That Luxembourgish is spoken at all today is a quirk of history - and particularly surprising since it bears little resemblance to either German or French. Although of Germanic origin (the earliest written reference is in monastic manuscripts from the 11th century) and still regarded by some as a West-Moselle-Frankish dialect of Germany, Luxembourgish has evolved so far from its parent language that it is no longer understood by most Germans. Many French words have also been adopted - only to be transformed almost beyond recognition. 'Elements of speech from Europe's pre-nationalist times are better preserved in Luxembourgish than elsewhere,' historian Bernard Nockels said. 'There are striking similarities between Luxembourgish and thieves' cant - the characteristic merchant and vagabond language of the late Middle Ages,' he said. So colourful and laced in curses is the language that he added: 'If a European championship in joke-telling was held, we Luxembourgers, as the best-armed linguistically, would hardly fear any competition.' Surprisingly, a dictionary and grammar for Luxembourgish were only created in the 1950s. A government publication on How to Speak Luxembourgish was not published until 1975 and the language has only been recognised as the national language since 1984. Until then, said government information officer Jean-Claude Muller, 'linguistic chaos reigned'. The legislative measure was an attempt to 'come as close as possible to the graphic of the two principal school languages, German and French', he said. However, Mr Muller said the roots of the Luxembourgish revival could be traced back to the Nazi occupation in World War II. In a 1941 referendum, 96 per cent of the population voted to tell their oppressors that their nationality and language was not German but Luxembourgish. 'Immediately after the war, there was a spectacular increase in the public use of Luxembourgish,' Mr Muller said. 'This was a natural reaction against four years of foolish linguistic tyranny, during which even the perpetual Luxembourg greeting, bonjour, was forbidden.' The adoption of Luxembourgish as the national language 'confirmed a real situation of trilingualism', he said. But it spelled the demise of German. 'The utilisation of Luxembourgish in public life, both spoken and written, is becoming more and more widespread in the Grand Duchy, while German seems to be losing momentum,' Mr Muller said. However, French continues to enjoy a certain prestige. With a third of the country and more than half the 85,000 residents of Luxembourg City being foreign - the highest proportion of foreigners in any European Union country - English is becoming an increasingly common form of communication.