What should one consider in choosing a language for web application development? [closed]

Question

To begin with, this isn't a question about which language one should choose :)

We're considering a language switch as our general direction is changing from content-driven web sites to data/action-driven web applications.

What sort of factors should one think about in order to successfully evaluate the various languages out there.

A few factors I've thought of so far, along with a supposed importance level:

• Level of knowledge of language X within the company [medium/high]
• Tooling available [medium]
• Community size & activity [medium]
• Availability of developers [medium]
• Cost of developers [medium]

Frameworks are also an important consideration, however I'm just trying to focus on the language-selection question first :)