We can classify words according to their Part of Speech (also known as Syntactic Category). Words that belong to different Parts of Speech have different properties, so identifying a word's Part of Speech is important for using it correctly. A word's Part of Speech affects two properties: where it can appear in a sentence, and which suffixes and prefixes it can take. 

Traditionally, some of the different Parts of Speech were defined as follows:
Noun: person, place, or thing
Verb: state or action
Adjective: describes a noun
Adverb: describes a verb, adjective, or clause
Preposition: Describes the location of a noun

The traditional definitions of Parts of Speech are not fool-proof. For example, the word destruction is an action so you might think it is a verb, but it is, in fact, a noun, while the word greed can be used to describe a noun, so looks like an adjective, but it is itself a noun. Sometimes, the same word can even appear as multiple different Parts of Speech. For example, the word work is a noun in I'll see you after work, an adjective in Did you wash my work clothes? and a verb in I will work all night. Linguists identify a word's Part of Speech by looking at its properties, but you can also figure it out by looking it up in a dictionary. If you would like to learn how to identify a word's Part of Speech, I suggest you sign up for a linguistics course at the closest muggle university!

The next 5 chapters deal with how nouns, verbs, and adjectives are formed in Latin. These are the Parts of Speech that are used most often in spell-casting, and also the Parts of Speech that have the most complex word-formation properties. Spells that use the other Parts of Speech--those listed above, and still others--will be discussed in chapter 12.

There are two types of prefixes and suffixes a word can take. In chapters 6-8, we will look at the inflectional suffixes of various Parts of Speech in Latin. Inflectional suffixes encode the grammatical properties of the word and can apply to nearly any word of a particular Part of Speech. For example, the English plural marker -s marks a property of a noun (whether it is plural or not) and can modify nearly any noun--except for a few irregular nouns. Afterwards, we will look at some derivational suffixes in chapters 9-10. Derivational suffixes change a word from one Part of Speech to another. For example, the English derivational suffix -er can take a verb like bake and change it into a noun like baker.