Most of the research problems I find enjoyable to investigate involve situations where the form of a word is affected by its place or role in the sentence. This domain is known as morphosyntax, a combination of morphology (word structure) and syntax (sentence structure). These are phenomena that are difficult to describe in terms of only sound and/or meaning. For someone who has not spent years studying language, the very idea of this may sound peculiar. Let me discuss a few specific topics, and you’ll hopefully have a better understanding of what my research investigates.
In the English present (or nonpast) tense, the form of the verb can change depending on the subject. We say I walk to the store but She walks to the store with an s on walks. For Standard English (though not all varieties!), it sounds wrong to say I walks to the store or She walk to the store. If you run through different kinds of English subjects (e.g., I, you, he, she, it, they, we, y’all, you guys), only some of them sound good with walks. This phenomenon is usually called subject-verb agreement because the verb and the subject must agree (or match) in certain properties. The verb appears in a certain form (walks or walk) to show that it matches those properties of the subject.
The curious thing about agreement is that there is no need for it. Plenty of languages do not have subject-verb agreement. For example, Mandarin Chinese does not have it. And speakers of languages without agreement have no greater issues communicating with each other as a result. But in many languages that do have agreement, leaving agreement out or switching it around sounds very strange. So, if agreement isn’t necessary for communication, what’s the point in having agreement at all?
That’s a pretty big question, and in order to answer it well, we need to first understand what agreement looks like in languages that have it. For example, what forms of agreement are possible or impossible? What forms of agreement are common or rare? These are the kinds of questions I have been interested in, always with an eye towards agreement’s place in human language.
As a small aside, I must note that agreement is more than just subject-verb agreement. Though I have written about subject-verb agreement, I have spent most of my time learning about what I (and others) call nominal concord. This is when modifiers of a noun agree with the noun. For example, in English, we can say these books or this table but not this books (different from this book’s!) or these table. I wrote my dissertation about nominal concord, and I have written a couple more papers since.
Many pronouns in English have different forms based on their role in a sentence. For example, let’s use the pronoun that a speaker uses to refer to themselves, I (i.e., the first-person singular pronoun). When we are the subject of a sentence, we say I like in I walked to the store, but when we are the object of a verb (or preposition), it’s me, like in The cashier greeted me. For many varieties of English, it sounds wrong to say Me walked to the store or The cashier greeted I. You can test the same form changes for some other pronouns in English (e.g., she/her, we/us, …), but some pronouns don’t change (e.g., you is always you). There are also some other forms that pronouns can take, like my or your to talk about owning or having something. When nouns or pronouns change their form based on their role in a sentence, e.g., subject or object, linguists call that case, or equivalently, case-marking.
Just like with agreement, plenty of languages get along just fine without case-marking. The World Atlas of Language Structures estimates somewhere between 38-48% of the world’s languages lack case-marking systems (depending on how you count). Most of the time, speakers can use the meaning of the verb and the context to figure out who is the subject and who is the object, so case-marking is in some ways superfluous.
Case systems get particularly interesting when they are compared with one another, and this is what linguists are usually interested in. What are the kinds of cases that show up in language after language? How do those broadly similar cases differ in fine details? And what does case-marking tell us about the connection between words and sentences more generally?
English’s system is actually relatively small. Only some of our pronouns have case forms. In other languages (like Estonian and Icelandic, my two primary research languages), nearly every noun in the language has case forms! In Estonian, if I want to say ‘A woman greeted me,’ the form of woman is naine. But if I want to say ‘I greeted a woman,’ the form of ‘woman’ is naist. It makes learning these languages as an adult very difficult. You can look ‘dog’ up in the dictionary, but in order to use ‘dog’ in a variety of sentences, you need to know all its different case forms!
The papers I have written about case (in Estonian) have had more to do with the case forms themselves rather than their connection to syntax, although my interest and expertise in case runs the gamut. Case also participates in nominal concord (see the Agreement section), so that has come up in those works, as well.
Noun Phrase Syntax
Most linguists believe that every language has nouns, which typically refer to people, places, or things, or so the grade school wisdom goes. It’s often the case when we use a noun that we don’t use it alone; we modify the noun with some other word. So, we can say I like cats, but we can also say I like fuzzy cats or I like those cats or I like those fuzzy cats. Linguists use the term noun phrase (NP) to refer to the phrases consisting of nouns and their modifiers. (An aside: some linguists call these things Determiner Phrases, so you might see that, too.)
One topic within NP syntax that I have written about is connected to what are called articles: the little words a and the in English that are very important to native-sounding speech but hard to pin down (have you ever looked up the definition of the?). English and many other European languages have articles, and in these languages, articles are often required. But other languages (like Estonian) do not. If an Estonian speaker wants to say ‘a man’ or ‘the man’, they just say mees ‘man’. In the paper linked in the first sentence, I investigated the details of noun phrase structure in Estonian, ultimately arguing that whether a language has articles is not in itself a deeply revealing property of the language, contrary to a popular strand of research of the past 25 years or so.
I have also written about numerals (aka number words) like one, five, or seventeen. Specifically I wrote about how they interact with plural-marking. In English, we say one cat and two (or more) cats with an s. But in many other languages (e.g., Turkish or Hungarian), you say two cat with no plural-marking. In Estonian, the more general pattern is like Turkish or Hungarian: two cat. But, for some nouns, Estonian actually puts plural-marking on both the noun and the number word, e.g., two-s scissor-s to mean ‘two pairs of scissors’. I collected corpus data to discover what kinds of nouns could be used with this double plural-marking in Estonian. I argued that, while some nouns have to use double plural-marking, any noun in the language can do so in principle, provided the context is right.