text: Rules specifying in which language a song may be performed have changed over time. No restrictions were originally enacted when the contest was first founded; however, following criticism over the  being performed in English, a new rule was introduced for the  restricting songs to be performed only in an official language of the country it represented. This rule was first abolished in , and subsequently reinstated for most countries in , with only  and  permitted freedom of language as their selection processes for that year's contest had already commenced. The language rule was once again abolished ahead of the .
  There is no restriction on the national origin, country of residence or age of the songwriter(s). Furthermore, unlike performers who may only represent one country in any given year, songwriters are free to enter multiple songs in a single year sung by different acts. For example, in the 1980 edition, both Germany's and Luxembourg's entry were (co-)written by Ralph Siegel, who – in a career spanning over 40 years – was involved in some form in the writing of dozens of entries — both advancing to the final and failing to make it past the national selection, including the winning entry in 1982.