"Community" includes turning to the person at the next desk and saying, hey, have you seen this before? Or asking on a mailing list inside your organization. That's why I said "people you know personally or professionally".
Sure, but I'd value a good general hackers opinion over a specific language specialist.
It really depends on your application domain. Someone knowing that the complex thing I want to do is already in NumPy and she used it herself yesterday and here's a snippet of code pasted into my IM is priceless. Similarly I might say, oh, I wrote some code that does nearly your thing, you could just change this one line. Pretty much anything I need I could code up myself in a half a day or a day, but all those half days add up.
More than one project I've started in Lisp here (not to pick on Lisp, just as an example) and run into an issue that I could implement myself in time T or do the whole lot in Python in time T/10. It's a no-brainer. For non-trivial tasks to be completed within fixed periods, striking out on your own with a new language is a meaningless risk.
PS I guess it varies between languages, but the wider community lists I'm on (Python, cx_Oracle, Matplotlib-users, Caml-list, a few others) are full of smart and helpful people.
If you run into issues, you need to be able to solve them. If the language is well documented, you can use that. If there are tons of books on the language, you can pick up a book.
I'd say asking the community is usually a last resort. Ever asked the PHP or Javascript community questions? Most of them have no idea. They'll give you terrible, often incorrect answers. Ever asked the Java community? Most will recommend you use XML to create a FactoryFactoryGenerator pattern on Jetty using enterprise beans. Ask the lisp community? They'll burn your house down for assuming you're worthy of asking them a question.
Obviously these are generalizations, and I'm sure there are some great javascript,php,java,lisp etc communities around.
Choosing the language based on the community amounts to just following the other sheep, rather than taking an unbiased decision about which language best fits the job required based on factors including libraries available, books, maintainability, ease of hiring people in later etc etc
Also I'd say communities like this (Hacker news) are far more valuable than specific language communities.