In this post I'm aiming to explain a bit about how adjectives with irregular degrees of comparison came to be that way and then describe an intriguing rule that seems to apply across almost all languages, but which linguists have not entirely explained the reason for.
Why do we have 'good, better, best' and not the 'good, gooder, goodest' we might expect from the overwhelming majority of adjectives, which form the comparative and superlative from the adjective itself (the positive) and adding -er and -est respectively?
The answer is that that there were originally two entirely separate stems, good and bot that somehow got amalgamated. Bot had a comparative bettra and a superlative betst and you can recognise these in the modern 'better' and 'best'. The meaning of bot was something like 'advantage' and it interestingly it still survives in fossilised expressions like 'to boot'
I am a citizen of the universe, and a gentleman to boot!
The first Doctor Who
So 'better' and 'best' displaced whatever were the original comparative and superlative of 'good' and this presumably happened before the precursors of English and German split, because German has 'gut', 'besser', 'beste'.
This phenomenon of part of a word family being replaced by words derived from a different root is called suppletion by linguists. (Something missing has been supplied.) We see it in action with 'bad' as well, with 'bad, 'worse', 'worst'' Here Old English had wyrsa, and wyrresta, but seems to have been a highly pejorative word until the Middle English period when it came into use as the positive associated with 'worse' and 'worst'. Incidentally these words may be derived from a root to do with confusion or mixup, which is also the origin of 'war'.
There is nothing special about English. Suppletion is common across languages and many have examples of adjectives with comparatives and superlatives which are suppletives. Latin even has examples of three distinct stems: bonus, melior, optimus.
Now linguists have noticed something that is true about degrees of comparison in (almost) all cases. It goes by the rather grand title of
The Comparative-Superlative Generalisation
and its says: if the comparative is suppletive, the superlative must be too, and vice versa).
In other words we can only have the patterns:
- AAA (as in English 'Big', 'Bigger', 'Biggest')
- ABB (as in English 'good', 'better', 'best'); or
- ABC (as in Latin bonus, melior, optimus).
So 'bad', 'worse', 'baddest' or 'bad', 'badder', 'worst' are both impossible. But why should this be?
The scholar J. Bobaljik argues that the superlative must build on the comparative (if it builds on anything), because it already presupposes a comparison, it cannot build directly on the positive.
This is very neat but to me not wholly convincing. How is that pattern ABC is allowed? What is the superlative building on in that case?
If this is not the explanation, then what is? Is then human brain 'hard-wired' is a way that excludes ABA and AAB? Or is it something innate in languages - might a Generative AI that invented a new language include a similar rule? This seems closer to Bobaljik's idea.
For a some relevant links see the comments.