There's a lot to discuss here. So let's take it point by point:
1) The Hofmann article is excellent. The only sad thing is that those writing in the Guardian and Observer didn't shout louder about things like this when Labour was in power. Then they could have done something.
2) All schoolchildren must, at about the age of eleven, be given the chance to acquaint themselves with at least one foreign language. I was not good at Latin at school; I'm still no good today, some 40 years later. But the fact I did that, French and some German there, meant that I at least knew what nouns, verbs, past participles, gerunds, conjunctions, conjugations and the rest were. That formed the basis for my good Dutch and Swedish, later on in life.
Schoolchildren are a captive audience. Few people are going to be enthused to voluntarily learn a language as an adult with no previous knowledge of languages.
3) Pesahson makes two valuable points: schoolchildren don't like maths, history, science either. And, a more important point, that DWM almost suggests, by the logic of his argument that Britons are less intelligent than foreigners because they find languages so hard. It is a question of motivation and some coercion. You simply cannot allow British schoolchildren to grow into adulthood without a knowledge of a couple of key foreign languages. Or ones spoken nextdoor, like Dutch and the Scandinavian ones. Teaching people Mandarin early on in life is a red herring. That is for trade only. If the Chinese economy collapses, no one will be interested in Chinese graduates. Whereas German and French are the languages of our immediate neighbours.
4) Starting to teach children languages before they have a solid grip on their mother-tongue is another politically correct exercise in making it look good. Make sure that eight-ten-year-olds know English well, before forcing them to learn other languages.
5) Britons, if they are to fit in during extended stays in countries abroad, would do well to learn the local language for social, as well as intellectual, purposes. Otherwise you will feel left out and will be shut out of much communication.
6) Let French be a "dead language". But it would be courteous to tell French-speakers (whether from France, Belgium, Canada or Congo) that their language is defunct - in their language. And this, of course, renders the language a living one, because you only pick quarrels in living tongues.
7) Let it be known: even I, a translator of literature from Estonian, don't speak it that well. Literary translation and pub chat require a very different approach. Words on the page don't move. Dictionaries exist and nuances can be found. But in a quick-fire conversation, you are soon out of your social and linguistic depth unless you can give as good as you get. It is not fun to be consigned to the baby-language corner while the rest of them are discussing Proust or insider trading using all the current expressions.
8) Learning another language after the age of say five is more difficult because your ability to pick up languages naturally diminishes with age. Hence all those "Teach Yourself" courses for adults. Schoolchildren are, at eleven, still a bit in the ease zone when it comes to learning. This is another argument for forcing children to learn languages, while their brains are still reasonably receptive.