I think this might a factor like (((medium term market size)-(availability of English in that country))*(openness to using English))/(difficulty of learning the language). It will differ between industries.

For people strong with English, I'd generally suggest: Spanish; French; Portuguese; German; Italian; Russian; Turkish and Japanese.

<blockquote>For people strong with English, I'd generally suggest: Spanish; French; Portuguese; German; Italian; Russian; Turkish and Japanese.</blockquote>
Good recommendations, Duncan - the other European languages would definitely come in handy.

My list would be similar, although I'd include Mandarin and Arabic in place of Turkish. But like you said, it really depends on what business you're in and who you are working with.

In the time it takes a native speak of a European language to learn Mandarin, they could learn four or five of the other languages I mentioned to an upper-intermediate level.

Yeah, I think learn a couple of European Languages aside from English would be beneficial.

Also Arabic and Mandarin will be very useful but they sound very funny and if you pick up those, they may well destroy your proper London or Munich accents that you tried to pick up

BTW, Is Arabic the main language of the Middle East gulf countries?

<blockquote>BTW, Is Arabic the main language of the Middle East gulf countries?
</blockquote>
Generally, yes. But depending on the country and your interaction, English can often be just as useful. For example, in the UAE, there has been an increasing adoption of English as the business language over the past decade or so. Some companies don't use English, though; and anything involving the government will most likely be completely in Arabic.

It's similar in Qatar: unless you're dealing solely with expats and multinational firms, it's probably good to have some command of Arabic if you're in business.