Its that time of year again: voices will be lost, throats will be hoarse, and all in the name of the highly anticipated Six Nations. But the author of a new book on the Welsh national anthem tells politicians, rugby players and fans not to sing Hen Wlad fy Nhadau on Saturday unless they truly believe and agree with the words.

Sin Jobbins, author of The Welsh National Anthem (Y Lolfa, 3.95) says that he'd rather have a quiet but honest stadium for the national anthem in Wales's opening match against Ireland, rather than 80 minute patriots sing the song without believing in the words.

When the anthem was composed by Evan James and James James, the Pontypridd father and son in 1856, some 80 per cent of the Welsh population spoke Welsh, explains the author. But as we've seen from the latest census results, were down to 20 per cent Welsh speakers by now. There's been a lot of singing in those 150 years, but not enough action. If the politicians, players and fans are serious about the anthem, then we all need to stand up and do our bit for the Welsh language. After all, it's the language which gives us the license to call ourselves a nation and have a national rugby team.

Coincidentally, Wales made history in 1905 by singing the national anthem for the first time at the start of a sporting event. Although hymn singing and singing the anthem were popular during matches, on the 16th of December 1905, the Welsh rugby players and crowd answered the New Zealanders haka dance with a rousing rendering of Hen Wlad fy Nhadau.

The national anthem is a fantastic song with a fascinating history. For thousands of us, o bydded ir heniaith barhau - long may the old language endure - is the most important line in the anthem, adds Jobbins. This line has sustained and challenged people for over 150 years. I love hearing the anthem at our international rugby and football matches, and wish it would be played when next a Welsh athlete stands on an Olympic podium, also.

The Welsh National Anthem traces the story behind the stirring song that, just because it was so good, became the nations anthem. The book also explains the meaning behind the words and includes a handy song sheet as well as an English translation and a phonetic version for learners. If youre committed to Wales then dont fail the John Redwood test, says Jobbins. Learn the words and learn the meaning. Its a rough-guide to the story of modern Wales.

Born in Zambia but raised in Cardiff, Sin Jobbins studied history at the University College in Aberystwyth. He is one of the founders of the dotCYMRU bid to gain status for Welsh identity on the web and is the author of The Phenomenon of Welshness.