What makes it possible to launch 10% faster? Is it familiarity with the language, tools, libraries, and frameworks? Is it that the language is more dynamic and requires less to accomplish task X? I would say yes to both questions.
Now with the first question, familiarity with the language, lets discuss Python. Python is my language of choice. I know it, I use it, I pay attention to what is happening with the language, the community, etc. I organize a Python User Group. If I were to work on a new project, I would choose Python. I believe I could launch 10% if not 50% faster with Python than with Ruby. Does that make Python a better language? No. Just that I don't know Ruby, Rails, Sinatra, etc.
I think the second question about how dynamic the language is plays into this as well. Java is not very dynamic. Some tasks in Java are downright ugly to work with. If you want to prototype fast and spit out a product fast, you might not want to use Java. At that point, there are several great languages to choose from like Python, Ruby, Groovy, Scala, Lisp, Smalltalk, Javascript, Closure, etc. The list just goes on. You could also argue that .net is more dynamic. But Java has some good points to it as well. You have less risk of bugs due to it being statically and strictly typed. You can build off some great libraries. You get the benefit of the JVM and JIT, which are amazing. Maybe you can't launch faster with Java, but maybe you can launch with a more robust stable product. First doesn't mean best; remember the article about Wasabi and Mint?
The way I read Peter's comment was you don't want to spend you time finding the best language. Instead you want to just grab the most convenient language and spend your time creating the best product. Think through your architecture, work on your design, test the hell product, study the market, your competitors, work on your marketing, and on and on. The list of things to do never end, and if you were still debating about which language to choose, you won't launch.
I agree. Language choice is definitely not the most important factor in success, but it's not as unimportant as some think it is.
Some languages make it easier to become familiar with the libraries. Compare the standard libraries of Ruby and Python with PHP. Even though I programmed in PHP for several years I always had to look up argument order, or whether the names of functions contained underscores between words or not.
Now with the first question, familiarity with the language, lets discuss Python. Python is my language of choice. I know it, I use it, I pay attention to what is happening with the language, the community, etc. I organize a Python User Group. If I were to work on a new project, I would choose Python. I believe I could launch 10% if not 50% faster with Python than with Ruby. Does that make Python a better language? No. Just that I don't know Ruby, Rails, Sinatra, etc.
I think the second question about how dynamic the language is plays into this as well. Java is not very dynamic. Some tasks in Java are downright ugly to work with. If you want to prototype fast and spit out a product fast, you might not want to use Java. At that point, there are several great languages to choose from like Python, Ruby, Groovy, Scala, Lisp, Smalltalk, Javascript, Closure, etc. The list just goes on. You could also argue that .net is more dynamic. But Java has some good points to it as well. You have less risk of bugs due to it being statically and strictly typed. You can build off some great libraries. You get the benefit of the JVM and JIT, which are amazing. Maybe you can't launch faster with Java, but maybe you can launch with a more robust stable product. First doesn't mean best; remember the article about Wasabi and Mint?
The way I read Peter's comment was you don't want to spend you time finding the best language. Instead you want to just grab the most convenient language and spend your time creating the best product. Think through your architecture, work on your design, test the hell product, study the market, your competitors, work on your marketing, and on and on. The list of things to do never end, and if you were still debating about which language to choose, you won't launch.