.. semi-transparent lettering? When you moderately cover one communiqu¨¦ next to another, the overlapping nouns mixes the two colours?
http://www.amazon.co.uk/101-80s-Hits-Var...
Answers: Adobe Photoshop (www.adobe.com) and Paint Shop Pro (now www.corel.com) both hold layering technique that you can use to mix colours.
Either Adobe Illustrator or Inkscape
Just adjust the transparency levels
adobe photoshop, or adobe flash (
http://www.adobe.com ) would be dutiful choices. Illustrator might seem to be difficult to a newcomer.