An interesting question popped up in our Gaelic class this week. We’ve been looking at comparatives and superlatives of adjectives lately, and just like good, better, best, Gaelic has a few that don’t conform to the regular paradigm. The word for small is one of them: we have beag (small) and lugha (smaller). A canny classmate asked: where does that mismatched lugha come from? In short: suppletion.

Suppletion is when parts of word patterns get replaced by bits from completely different places. The term derives from Latin supplere, supply, and that’s quite apt – one pattern is supplying another with its own bits and pieces. 

For a look at the irregular havoc suppletion can wreak, just see what happened to good in the Germanic languages. Instead of gooder and goodest we have better and best, which don’t bear the Good family resemblance one bit. So where did adoptive better and best come from, then? Well, there seem to have been two synonymous words for good in Proto-Germanic: *gōdaz and *bataz – and for whatever reason, they became mushed together, with the *bataz bits filling in for the comparative and superlative of *gōdaz.

The Road to Suppletion

As with many odd irregularities, it’s the kind of thing that happens to paradigms that are in frequent use. For instance, super-frequent good-better-best has irregular comparatives in the Romance languages too (French bon – mieux), as does bad–worse-worst (Spanish malo – peor). The patterns for large and small often get grafted onto too, although that fate hasn’t befallen the English versions (yet). Not so for Gaelic (or Irish, for that matter) with that beag – lugha mix.

The origins of lugha aren’t that obscure, as it turns out, as lugha appears to be cognate with the English word light (as in as a feather). In terms of meaning, it’s pretty close; you can imagine speakers conflating small and light, especially referring to food or other goods. The result is that small – smaller somehow became small – lighter, beag – lugha.

So much for small, then. But what happened to light, if beag had pinched its superlative for itself?

As is often the case, it seems to have simply faded away, just as the non-comparative grade of *bataz has left the Germanic languages. The words for light in Gaelic and Irish are now remodelled versions of ‘un-heavy’ – aotrom and éadrom respectively (from trom, heavy).

The Etymological Rabbit Hole

All in all, tracing the winding etymological of suppletive paradigms paints a fascinating picture of one type of language change. Following up on these hybrid etymologies via resources like Wiktionary can provide some real insight into both how your target language evolved over time, and how it is related to other languages.

The remnants of many a forgotten root lie along the road to suppletion.