(Original post by Anatheme)
There is so much rubbish in these posts, I don't even know where to start. What makes you so qualified to say that Mandarin is harder than say Arabic, Russian or Korean? The difficulty of a language depends on the learner's motivation and their background in language-learning. It will be harder for someone with little experience of learning languages, but it'll be equally difficult for someone who's mastered a few languages but has no interest in Mandarin.
You mention that Chinese culture will be exported, and I'm afraid I can't see that happening anytime soon (certainly not in the next 20 to 30 years). The globalisation of culture is mainly done through English, which is arguably an easier language to learn than Mandarin for the majority of people in the world. It's a process that started a while back, and hasn't shown any signs of decline so far. There is also the fact that Chinese culture is really quite niche and not as easily exportable as you might think, they don't have the same interests, the same humour, etc. This is exactly what makes China such a closed country - they have their own culture and don't really need to rely on others to survive.
The fact that China is such a closed country actually makes it difficult for foreign businesses to get started over there, and there's an interesting article right here
about it. There's a few people on TSR who work in China and could even tell you about the phenomenon. China doesn't want to share, they'd rather have it done their own way, and I'm not sure learning Mandarin or Cantonese for the sole purpose of getting a business-related job is a good idea, nor is it a good investment. It is a language that's difficult for most English natives and the amount of time you will have to dedicate to learning it could arguably be better spent learning an "easier" language.
There is also the fact that, as applies to Arabic (think UN and businesses, here), employers prefer to hire native speakers of Mandarin, simply because it's less hassle to teach them English (which they might well have learnt already by having done their studies abroad) than it is to teach an English speaker a foreign language, as native speakers of English have that terrible tendency to think that everyone in the world speaks English and that learning a language is thus a waste of time because repeating what they just said loudly and slowly solves everything. It doesn't, it just makes you sound like an obnoxious ****.
Now regarding French, I don't know how you came up with those "facts", but they're pretty appalling. Since when the number of speakers of a language define its power? There's more people speaking Javanese and Marathi than French, that doesn't make them any more "useful". French is still a very important diplomatic language (it's, with English, the only working language of the UN, the other four are generally translated when used, but not French) that is used by a very important amount of NGOs and other organisations. If you are interested in working for the EU, the UN, NGOs, development, etc. you'd better have French under your belt.
And as a matter of fact, French is more important than English in the EU. Why? Because it's not just France (which also happen to be one of the biggest countries in the EU) speaking it, but Belgium, Switzerland and Luxembourg. You'll notice that most of the EU institutions are based in countries speaking French, and it's often a requirement to have French if you want to work for the EU. When it comes to the rest of the world, it's a language that's spoken on all of the continents (and there are definitely tonnes of African people speaking French, just have a look at the number of countries having it as their official language
, and you can even add the Maghreb countries…), and depending on which field of work you want to go into, it's likely to be of some use.
French can be useful for politics and diplomacy (EU, UN), but it's also a major trade country in the EU, due to its location and its size, so you'd be silly to dismiss it that quickly. If you're into computer games, there's a growing industry set up in Paris, if you prefer cars there's a few important brands exported everywhere in the world that I'm sure don't need to be introduced anymore, if you prefer aeronautic or aerospacial engineering, Airbus and the CNED are pretty important. Physics? Look at where the CERN is, and you'll notice it's the French-speaking part of Switzerland. Sure, you can learn German or just be ok with English, but having French will help you in these spheres. It's not essential, but if you look at it from this point of view, then I guess no language is essential…
Finally, as it's been said before, you shouldn't think of a language as a sole mean of communication and you shouldn't force yourself to learn one because it's good for your CV. Learning a language implies learning a new culture, and if you have no interest in the culture, it'll make your language-learning experience a lot harder, and a lot less useful, for you'd miss out on culture-related subtleties that often are the most important part of a language.