What does "diametrically opposed" mean in this context?

Question

Only one traditional BE phoneme has been omitted from the consonantal inventory, this being the aspirate, and the typographical signal of its absence – the apostrophe – is regarded as a regrettable relic of an age when Bourgeois English posed as a standard to which other varieties (rural, industrial and colonial) aspired. The following sentences are considered orthographically correct:

Enry Erbert Iggins, being ot and in a hurry, ad to ang is at up in the all.

E’s a orrible unk of atefulness.

On the other hand, the aspirate is to be retained as an emphasizer, only initially however, in such statements as, ‘I said, eat up my dinner, not heat it up’ (the meaning here being diametrically opposed to the meaning conveyed by a speaker of BE when uttering this sentence).

- 1985 by Anthony Burgess

In this part of the book Burgess talks about an artificial language called Bourgeois English. And some words, phonemes etc. are omitted when creating that language. One of them is aspirate. Which I understand as the sounds that are denoted by the letter "h" - as in house.

But I don't understand what author means by the sentence inside brackets (bold by me). Does he mean that:

the intention of writing the sentence in quotes 'I said, eat up my dinner...' is not to deliver the actual meaning of it. It was just to demonstrate how to "h" sound works.

Or what does he mean by that?

Answer 1

"diametrically opposed" means exact opposite (in some context)

The translation, of the WE sentence "I said, eat up my dinner, not heat it up", to BE is "I said, heat up my dinner, not eat it up". The WE meaning is the exact opposite of the BE meaning.

Remember Burgess is having fun and making a point: the point being that the language of the "workers" can be subject to formal grammatical description. It is not the case that the utterances of the "workers" is less grammatical than that of the bourgeois, just that the grammar is different. He makes this point by supposing a formal dialect called Worker's English. Note that the aspirate "H" is omitted in Workers English and not in Bourgeois English.

It's not a real language. Don't suppose you should treat this as a grammar textbook.