Choosing Programming Languages for New Projects: Old Language, Old Project - Or New Language, New Project?

How do you decide which language to use when starting a fresh project? Some follow the adage "new project—old language, old project—new language." But what's your approach?

Some points to discuss:

• Decision criteria and heuristics for language selection
• How to balance comfort with growth
• Learning fatigue vs. focused depth: navigating the challenge of learning a new language PLUS building a new project simultaneously

Everyone and anyone is welcome to join as long as you are kind, supportive, and respectful of others.