Further information

     The white egg is the biggest and the red egg is the smallest. 

We use superlative adjectives of superiority and inferiority to compare more than two things or people. 

The construction usually depends on the number of syllables. 

 Inferiority 

Note that we rarely use this construction with one-syllable adjectives. It is better to use the opposite superlative of superiority.

The comparatives and superlatives of most two-syllable adjectives are formed with 'more...than' and 'the most' but here is a list of some common ones that can also add 'er' and 'est'.  

If the adjective is also the past participle of a verb, we do not add 'er' or 'est' even to short, one syllable adjectives. Instead we use the rule for long adjectives.

Examples

With superlative adjectives, we use 'by far' and 'easily' as intensifiers. For example: 

Our company sells by far the most cars in Europe.

She's easily the tallest person in her family.  

One-syllable adjectives

Most of these take 'er' and 'est' for superiority but there are a few, particularly some ending in 'l', that are better with 'more...than...' For example:

I'm more apt to forget things when I'm tired.

Some dreams seem more real than others.

And there are a few others which can use both forms. For example:

            She's frailer/more frail than her sister.            

That's clearer/more clear now - thank you for explaining.

It would be fairer/more fair to divide it equally.

For inferiority, most take 'not as...as...' but a few use both forms. For example:

It isn't as cold as it was.

It's less cold than it was.

            Riding a bike isn't as safe at night.

Riding a bike is less safe at night.

'All the more'

This expression means 'even more than previously or otherwise'. We can use it with adjectives or adverbs or with neither. We can also use 'all the less' in a similar way as well as 'all the' + comparative adjective or adverb. For example:

I really can't wait for my holiday and it's all the more exciting for being outside Europe - it will be my first time.

We were already doing well and we worked all the faster when we heard there'd be a bonus for finishing before the deadline.

We've never had much faith in him and his arguments are all the less convincing when you consider his lack of experience.

I'm starting to recover now and I feel all the better for your visit - thanks for coming.

Note that 'even more/less' or 'even + er' are generally more common in conversation.

Comparing two qualities

We don't use 'er' to compare two qualities of the same person or thing. For example: 

Similes

We use 'as...as...' in similes - standard expressions which use a comparison of two things that are alike. It's an alternative to using 'very' or 'really'.  

Her hair is as white as snow.

I love cycling here - it's as flat as a pancake

It's impossible to make him change his mind - he's as stubborn as a mule.

There are many of these in use in informal English and they are often used in a fun or joking manner.

Note that we cannot use 'so' in similes.

Superlative adjectives with 'the least'

With one-syllable adjectives, we usually prefer to use the opposite adjective of superiority:

This is the least dark colour.           This is the lightest colour.  

With other adjectives, both are often possible:

This is the least expensive car.      This is the cheapest car.

However, we need to be careful because these kinds of sentence don't always have the same meaning. For example:

'February was the least cold month of last winter' isn't the same as 'February was the hottest month of last winter.' [because none of the winter months were hot.]

'So'

For comparatives of inferiority using 'not...as...', we can substitute 'so' for the first 'as':

He isn't as/so tall as his brothers.

'not as...as...' is more common. 'not so...as...' is more likely to be used with ellipses than in full sentences:

It isn't  so cold today. [as yesterday]

People aren't so poor nowadays. [as they used to be]

Note that we cannot use 'so' in comparatives of equality:

           It's as cold today as yesterday.            It's so cold today as yesterday.

or in the following similar kinds of expression: 

I drove as fast as I could.                I drove so fast as I could.

I'll call him as soon as possible.    I'll call him so soon as possible.

However, 'so' is possible in some expressions which are not comparatives. For example:

'as/so far as' = to the degree or extent that

'as/so long as' = on condition that or since

As/so far as I'm aware, there's no meeting this week.

            As/so long as I get paid extra, I'll work on Saturday.

            As/so long as you're dealing with this, I'll go to lunch now.

'Most' as an intensifier

The word 'most' can be used in a way that is not a superlative. It has the same meaning as words like 'very', 'really' and 'extremely'.

Note that this structure is rarely used and sounds old-fashioned so do not use it. The following examples are for information only :

* It is much more natural in conversation to say:

I read a really interesting article.

This soup is absolutely delicious.

Other comparative and superlative structures

Here are some examples of different ways to express comparatives and superlatives:

It was as successful a venture as he could have hoped.

Their request deserved as quick a response as we were able to give.

It's isn't as much fun working here as it used to be.

I have a much faster journey to work now.

A male-dominated company is less likely to offer flexible working hours.

The most likely outcome is that sales will start slowly and take off later in the year.

It isn't as high quality as the previous model.

What's most important to me is job satisfaction.

What I like best about him is his ability to explain things clearly.

He lived the longest of all his family.

I like most kinds of cheese but my favourite is Camembert.