Many of the responses to the ideas concentrated on the fact that at the same time as Cameron is pushing for English to be learned, he has managed to slash budgets for ESOL teaching, thus reducing the chance of non-English speakers actually learning the language. Others noted that along with an encouragement to learn English, the threat of deportation was also lurking. They pointed to the line "We will now say if you don't improve your fluency, that could affect your ability to stay in the UK". Tied to the apparent encouragement for Muslim women to learn English was also a threat to punish them. And why single out Muslim women? Would English ex-pats who live in Spain but don't speak a word of the local language beyond "cerveza" be deported by the Spanish authorities for not speaking a word? And would the knuckledragging keyboard warriors of far-right organisations - born, bred, and supposedly educated, in this country - be sent back to their mums for not being able to spell "Go hoam immagrnat"?Finally, Anita Anand noted that the UK government website couldn't actually manage to spell "language" properly in its own tweet. D'oh!
Obviously, English can be a unifying and integrating force for good: if we can all talk to each other, the argument goes, we can all start to get along. But the imposition of English on people has a long history of problems. English is not just a language of the world because it's flexible and absorbent (like your favourite kitchen roll) but because it has often been accompanied with political and social systems that have forced it on others, often at the end of a gun. There's nothing intrinsically better about an English speaker than someone who speaks French, Cantonese or Yoruba, but many still cling to the colonial belief that English can be a "civilising force" on Johnny Foreigner.
But English can also be something that allows people to feel part of a wider community and that's why so many people want to learn it - in the UK and beyond - and one reason why teaching English as a second language is so important. If Cameron were really serious about the power of language, he wouldn't be singling out one group of people or cutting funding to ESOL and the FE sector that are so vital in its provision.
Edited to add:
Frank Monaghan has written an article here which is worth a read.