In the UK and, I'm sure, in other English speaking countries their slogan is 'I'm luvin' it.'
Luvin' is supposed to mean 'loving.'
In English, whenever we use the phrase 'I am xxxxxing (something) this is an example of the present continuous tense - for example - 'I am looking for my cat.' It is used to describe or explain what a person is doing now.
BUT - in theory, McDonalds have got things badly wrong in their advert. Our grammar books tell us that we can only form a continuous tense using 'dynamic verbs.' A verb that is 'dynamic' can be made into the continuous form by adding + ing. For example: look becomes looking, talk becomes talking and enjoy becomes enjoying.
But the verb 'to love,' is not on the list of dynamic verbs. So it is wrong (in theory) to say 'I am loving it.'
But this is a perfect example of where the rules in your grammar book and the way that English is really spoken are two totally different things.... In truth it is not only McDonalds that 'get it wrong.' On a daily basis people in England say things like 'I am loving the new series of Downton Abbey.'
So.... How to deal with this as a learner of English?
If you are doing a formal test then you should look up a list of something called 'stative verbs.' This is a list of verbs that are not dynamic. Avoid using the stative verbs in continuous forms (including the past - for example 'I was loving this,' or the future - for example 'I will be loving this.'
Otherwise? Feel free to say 'I'm loving it,' because real English people say this all the time.
I'm sure some teachers would say we should always correct everything in the way the grammar books suggest. But making yourself understood is about speaking in a way that a native speaker would understand, in my opinion.
What do other teachers and students think about this point, both in general and in the case of the way McDonalds use their slogan 'I'm luvin it'?
Teachers - do you spend your time correcting 'stative verb,' errors? Or do you only correct the errors that involve verbs that native speakers really, genuinely, do not use in the continuous tense?
Students - do you prefer to speak in a grammatically perfect manner? Or would you rather your teacher correct only errors - such as those with pronunciation or using the wrong word, that could stop people from understanding you?
... You are, of course, totally correct that "I love it," would be a useless slogan.
It would be okay (according to our grammar books) to say "I'm relishing it," or "I'm enjoying it," but these do not really work either.
Then again, "I'm relishing it," could be a double entendre - after all, it (relish) is sometimes included along with the gherkin in your burger..
For students - the verb "to relish," means to really enjoy something. But 'relish,' is also a noun for a type of slightly think sauce which is put inside the bun with a burger, or which you might eat with cheese. If you've never tried a relish, I definitely suggest that you try it with cheese!
A double entendre is a word that has two meanings..
It's a good question. I've just checked the Macca's Australia site (yes we call it Macca's), and it's presented exactly as below:
i'm lovin' it
So not only do we have an "error" with the verb form, but also a lower-case letter in place of a word which is always capitalised ("I'm").
So what if the slogan were grammatically correct?
I love it.
...which sounds so mundane and unimaginative, it's absurd. :) I'm sure McDonald's has deliberately chosen these "errors" to grab our attention. I think the phrase "I'm lovin' ___" was already in use when the slogan came out, and McDonald's picked up on that to reflect the current speaking trend.
As native speakers, we have a better sense of what to take at face value, and what to take with a grain of salt. We certainly know what phrases are appropriate in what situation.
For learners... well, it's a lot trickier. I think a lot of casual speech, pop culture and slang gets taken literally by learners, and without guidance they might assume it's "real" or "better" English than what they learn as standard English. There's a lot of nuance to learn!
As for correcting students, I explain that the so-called standard English should be their starting point and first option. If they manage to use casual forms in the right situation and sound natural doing so, then that's fine. If one of their aims is to speak English well and be taken seriously (and professionally), then they need a correction.