[alexbecker]

When I worked on Google AdWords, i18n was a huge deal despite it being a business-facing product. More than half of the revenue came from outside the US. I'm not sure what percentage wasn't in English, but it had to be large. I regularly got users filing bugs against me in Easter European languages or in Arabic (these seemed to maximize buggyness * number of users). So there is definitely money to be made selling to non-English speaking businesses, especially when the competition isn't.

That being said you need to actively pursue international sales for this to work, and i18n software is only a part of this. If you aren't making the effort on the sales side it probably isn't worth it on the engineering side.