Anyone remember my tutor? He told me there's no such phrase as 'much more happier, much happier, more happier' or in other words he said it's gramatically incorrect.

Is it true? I see a lot of people use those phrases and I do notice that it doesnt fit to put much/more to a comparative such as happy but I see that that pattern of phrase is widely used around the globe.

Is he correct to say 'much more happier, much happier, more happier' is gramatically incorrect?
According to the rule most people know, he is right. However, there are some exceptions (of course...)

This is the basic rule most people know:
- When there is one syllable in the word, the word is simply conjugated, most of the time by adding '-er'. For example, small becomes smaller, great becomes greater, and so on.
- With more than one syllable int he word, the word is not conjugated by adding anything to it, but simply by putting 'more' before the word. For example, beautiful doesn't become beautifuller, but more beautiful.

As happy knows more than one syllable, happier should not exist at all. However, you are right that English people can say they are 'the happiest people in the world'. This as to do with the suffix of the word. Words ending in a consonant + le, er, ow, y, some serve both options. Noble can become nobler or more noble; clever - cleverer or most clever, and so on.

Hence, happy (ending in a consonant + y), can both become 'happier, happiest' and 'more happy, most happy'. I believe the former is more common than the latter, but I leave that to native speakers...

"More happier" is definitely not correct as a comparative, since it would mean "more more happy".

I don't see why "(much) happier" should be wrong, and it sounds to me much more natural than "more happy".
what about much more happier?
If "more happier" doesn't work, "much" isn't going to change anything, alas... Emotion: sad
The general rule is

when the adjective has 1syllable you can simply add -er....e.g. short - shorter

adjectives with 2 syllables that end in -y change the y to i and add -er......e.g. funny - funnier

other adjectives with 2 syllables or more than 2 use more .....e.g. more modern

There are usage exceptions such as little, littler. These can be found in a good learners dictionary like the Co-Build.

Hope this helps.

P.s. remember to double the consonant when the adjective ends with a consonant-vowel-consonant combination e.g. fat - fatterEmotion: wink
Vince you are right, but as for the first comment, more happier does not exist and is completely incorrect. you can either say more happy, or happier, but more happier is wrong.
The usual way to compare a two-syllable adjective ending in –y, like happy is to change the y to I and add –er.

If we use "more happy" instead of "happier," it means the same thing.

We might use "more happy" in a situation in which the word "happy" has already been mentioned, or is definitely known, as in these examples from the New York Times:

"¢ What you think you should do to be happy, like getting fitter and thinner, is part of a "cultural code" "” "an unscientific web of symbolic cultural fantasies" "” and once you realize this, you will perhaps feel a little more free to be a lot more happy.

"¢ ''I was more happy for her because she made the decision,'' Freeman said. ''I know her well enough to know she's a very proud athlete, and I respect her for what she represents.''

''She decided she wasn't ready to run and she didn't want to run,'' she added. ''The only important thing is that she's happy.'' (This is about Freeman's meaning that she is happy for herself, but even more happy for another person.)

Or, if two adjectives are being compared and the other one would take "more," "more" can also be used to compare "happy," (or another two-syllable adjective ending in –y):

"¢ But after arriving in Indiana with his wife, Alice (Mariel Hemingway), and daughter, Terri Jo (Melissa Ann Hackman), Bud gets a reminder that the Parks family is no more happy or stable than it has ever been.

Occasionally, someone just chooses to use "more happy" instead of "happier":

"¢ Sabine's critique is not trustworthy. In Byatt's collection of tales, the oral and the written traditions could not have a more happy marriage.

The usual way, of course, is to add –er to the two-syllable adjectives: happier, easier, busier, prettier, lazier, etc. It is possible to use "more" instead of –er, and, although not grammatically incorrect, it is not frequent. "More happy" might be used in the special cases, as in the first three examples above. The meanings of "happier" and "more happy" are the same.