When we learn a language, there are two types of things we know. First, we know the descriptive grammar rules of the language, which we will learn more about in Chapter 3, and we know vocabulary from the language.

We store our vocabulary in our mental lexicon. The lexicon is the part of our memory where we store our knowledge of all the words we know. This includes how to pronounce the word, what the word means, and anything else about the word that is not predictable. That is, anything about the word that we have to memorize rather than that we can predict based on the grammar rules of the language. For example, for a noun with an irregular plural like child ~ children or a verb with an irregular past tense like go ~ went, we would have to store the irregular form in our lexicon. But for nouns with regular plurals like cat ~ cats and verbs with regular past tenses like walk ~ walked, we would not store it, instead we would build it from the rule. Likewise, some complex words have unpredictable or non-compositional meanings. For example, the word edible doesn’t simply mean “can be eaten”; it means “can be eaten without ill effect to your health.” The idiosyncratic component of meaning must also be stored in the lexicon.

Psycholinguistic studies show that productive complex words that are frequent may also have their own entries in the lexicon and may be accessed as unanalyzed wholes (Sims-Williams 2021). This means that in future language change, the stem and the complex word created from it might take separate paths — one can pick up idiosyncratic meanings or take on changes in pronunciation that the other does not. Some examples of this include brother, which formerly had an irregular plural brethren. The irregular plural picked up an idiosyncratic meaning (religious co-affiliation) and a new, regular, plural form, brothers was coined. Likewise, the plural of cloth used to be clothes. The irregular plural picked up the idiosyncratic meaning of garment and a new plural, cloths, was coined.

Deciding exactly which parts of language are productive, and can be built from our grammar rules, versus which parts of language are memorized in our mental lexicon is an important question in the study of morphosyntax. Another related question is when we access the lexicon as we build our sentences and words. There are three main options:

1. We access the lexicon only at the beginning. We pick out which words or morphemes we are going to use at the beginning of the process, and then we move them to a workspace where we can combine them to build a structure.
2. We access the lexicon only at the end. We build a structure using abstract pieces, and then we plug in the appropriate words at the end.
3. We access the lexicon multiple times throughout the process, inter-weaving the selection of words and the building of structure.

Dictionaries

A dictionary is kind of similar to a mental lexicon, because it also records the vocabulary of a language. But there are some important differences between a mental lexicon and a dictionary, as summarized in Table 1.

Some of the things we will learn together are things that you might be able to look up in a dictionary, like the part of speech (noun, verb, etc.) of a word. But in this course (and most linguistics courses), we want to learn how to figure it out ourselves, not how to look it up. There are a few reasons for this. First of all, dictionaries aren’t always accurate. As mentioned in Table 1, dictionaries often lag behind language change and also only include the most common or standard patterns of language. In our linguistic analyses, we want to consider all the possible structures, not just the most common ones. Second, as a linguistics student, you are training to become the kind of person who will one day be qualified to write dictionaries. You can look things up in a dictionary to confirm your analysis or get a second opinion, but if you depend only on the dictionary, then you are skipping part of the learning process!

Check yourself!

References and further resources

For a general audience

🧠🔍 Curzan, Anne. 2014. What makes a word “real”? TedxUofM. https://www.ted.com/talks/anne_curzan_what_makes_a_word_real

For linguistics students

🧠 Anderson, Catherine, Bronwyn Bjorkman, Derek Denis, Julianne Doner, Margaret Grant, Nathan Sanders, and Ai Taniguchi. 2022. Section 7.4: The mental lexicon. Essentials of Linguistics, 2nd edition. https://ecampusontario.pressbooks.pub/essentialsoflinguistics2/chapter/7-4-the-mental-lexicon

🧠 Anderson, Catherine, Bronwyn Bjorkman, Derek Denis, Julianne Doner, Margaret Grant, Nathan Sanders, and Ai Taniguchi. 2022. Section 7.10: Why not the dictionary? Essentials of Linguistics, 2nd edition. https://ecampusontario.pressbooks.pub/essentialsoflinguistics2/chapter/7-10-why-not-the-dictionary

Sources for examples

Pentland, David. 2023. Proto-Algonquian Dictionary: A Historical and Comparative Dictionary of the Algonquian Languages. Winnipeg: Algonquian and Iroquoian Linguistics.

Academic sources

Sims-Williams, Helen. 2021. Token frequency as a determinant of morphological change. Journal of Linguistics 58 (3): 571–607.