Parts of Speech
Let us begin with some simple observations: Biologists tend to classify living beings on the basis of certain features. Mammals, for example, are vertebrates that lactate and have fur. So what biologists do in this case is put animals in one class because they share certain characteristics.
In a very similar vein, linguists classify words on the basis of certain features these words have in common. The classes that we use are called Parts of Speech (or lexical categories, or word classes). In every sentence, every syntactic word has a part of speech.
But how can we tell whether, say, a verb is a verb? As a first approximation we can say that verbs refer to events. In other words, a verb's meaning has to do with events. Correspondingly, we can say that a noun denotes an entity, adverbs modify events and so on. You can call the classification of words on the basis of their meaning a semantic criterion.
Approaching the classification of words by their semantics is fine, but doing so exclusively has certain shortcomings. Take, for example, the above definition of a noun, and consider words like sand. What kind of entity does the word denote? It will be hard to define the word exclusively on the basis of semantic criteria. Luckily, another approach is at hand. Consider the word jump. We know that, in English, a tense affix (-ed) and a third-person singular (-s) affix can be attached to verbs. Hence we derive:
jump - ed jump - s
So we might generally say what makes a verb a verb is the fact that they take agreement and tense morphemes. Looking at the "shape of a word" to determine the class the word belongs to can be called a morphological criterion.
Again, the determination of a word's class on morphological criteria alone has its limits. Take, say, the word dead. Assuming that adjectives can be grouped together on the basis of their having degrees (i.e. they characteristically have a comparative and a superlative), this word poses a problem for the criterion, since it arguably does not have degrees: *dead-er, *the dead-est.
Two Basic Subtypes of Word Classes
In linguistics, a basic distinction is made between words that are more lexical, such as nouns and verbs, and words that are more functional or "grammatical", such as determiners or conjunctions. Based on this distinction, the parts of speech are grouped into
Follow these links to get the details about the different parts of speech in English!
Related ELLO-pages and Links
- For some general comments on parts of speech, see the page on Lexical Categories from the General Linguistics (Syntax) section of ELLO.
- Parts of speech are also important in the context of Corpus linguistics. The set of part of speech labels (or pos tags) used in the British National Corpus (BNC) is particularly important for us. Here is a link to the pos tags used in the BNC.