How word storage influences our language production

Date of news: 30 September 2021

In Dutch, the plural of some words can be formed in two ways, as with aardappel (potato): both aardappelen (potatoes) and aardappels (potatoes) are correct. Linguist Tim Zee used this plural variation to investigate how different processes play a role in human language ability and how they interact.


The plural of piramide (pyramid) can be either piramiden or piramides (both mean pyramids). Dutch has more of these variable plurals. Both forms are correct, but which processes in our brains play a role and how do they interact? Linguist Tim Zee and his colleagues did two corpus studies to find out.

Distribution of variants

In the first study, Zee investigated how the distribution of the plural variants is established. Why are the plurals of some nouns formed by adding -en to them and others by adding an -s? Zee: 'The most accepted answer is that there are general patterns that determine which ending is given to a noun with certain formal characteristics. For example, a noun that ends with an unstressed syllable often ends with an -s. A noun that ends with a stressed syllable often gets an -en. It seems that Dutch has a preference for a stress followed by no stress at the end of a word. We call that a troche. But sometimes those patterns conflict with each other, or there is no clear preference. That is the case with pyramid in Dutch: you can put both an -s and an -n after it and in both cases you have a trochee at the end.'

More frequent plurals

Linguists looked at whether these patterns can fully explain the distribution of plural variants in variable plurals: when do people go for aardappelen and when for aardappels (potatoes)? ‘We have created a model that explains non-variable plurals, such as bakkers (bakers) and pirates (pirates)’, explains Zee. ‘We then looked at whether we could also use that model to explain the distribution of variable multiples. For example, can we use the patterns in the model to explain why it is piramides in 56 percent of the cases and piramiden in 44 percent?'

The study shows that for nouns where the plural is more common than the singular, the generalization of general patterns has less influence than for nouns where only one plural form is possible. This can be explained as follows: because plurals that occur more often than the singular have stronger representations, we do not need to compose the plural from a singular with a plural ending. The plural is ready in our head as a whole. So, generalisation has less influence, because that pattern plays a role in forming a plural from a singular. ‘That means that generalization and word storage interact,’ concludes Zee.

Pronunciation of s plural

In the second study, Zee investigated how the pronunciation of variable plurals is influenced by the mutual frequency of the variants. Zee: 'We knew from the frequency distribution between the plural variants from the first study. And then we looked specifically at the pronunciation of the s-variant. Does the distribution of the variants influence the strength and duration of the pronunciation of the s?' Based on previous research, Zee expected that if the s-variant is more frequent, the s will be pronounced longer. ‘That's because the mental representation of that variant is stronger compared to the alternative variant. So, there is less competition from the alternative variant, which leads to a stronger pronunciation.'

In speech, many words are not fully pronounced. This is called reduction and it often happens with more frequent language elements, such as it’s for it is. But if there is uncertainty about which word to choose, then the more frequent or more likely element is pronounced in a less reduced manner. The idea is that both elements - in this case, plural variants - are stored and that they are both active during and have an influence on the pronunciation. But if one variant is much more frequent than the other, there is less competition and the pronunciation is less distorted and therefore stronger. ‘By the way, that statement is not accepted by everyone. It is still being researched. For our study, we assumed that this mechanism is at work because in our case the alternative elements (plurals) really are both correct. That has been less clear in previous studies,' says Zee.

With this mechanism, Zee assumes that the plural variants are stored. The first study showed that plural forms are mainly stored as a whole if they are more frequent than the singular. The effect of mutual frequency should therefore also be especially clear with those kinds of plural forms. 'In other words, we should therefore mainly see the consequences of competition between variants of pronunciation if the plural occurs more often than the singular,' says Zee. ‘That's also what we find. Competition, in this case, relies on word storage. The innovative thing about our research is that we have used pronunciation to demonstrate this, which had never been done before.'

Knowledge about language ability

Zee's research provides evidence that word storage plays a crucial role in morphologically complex words – in this case plural variants. Word storage affects both generalisation and competition between word forms. But why do we want to know that? A good question, says Zee. ‘This research is very fundamental. There are no direct practical implementations, but it does contribute to our understanding of the human language ability. The more we know about that ability, the better we can design our teaching techniques and the better the technological applications become.’

Further reading: Paradigmatic Relations Interact During the Production of Complex Words: Evidence From Variable Plurals in Dutch