[sanswork]

A lot of people get hired in for emergencies. In such cases waiting for person to learn your offices language of choice isn't ideal.

[TFrancis]

Though they aren't always possible to avoid, I consider "emergencies" examples of poor business decisions and try to avoid them.

[Xichekolas]

While I can see some merit in this argument, I'd also point out that I've never met a decent programmer that can't pick up a new language at least passingly in a day or two.