English: Word Classes

1. Open and Closed word classes

1.1. Open word classes: the category of content words—that is, parts of speech (or word classes) that readily accept new members. The open classes in English are nouns, lexical verbs, adjectives, and adverbs.

1.2. Closed word classes: made up of finite sets of words which are never expanded. Typical closed classes are prepositions (or postpositions), determiners, conjunctions, and pronouns.

2. Compounding, derivation, inflection and conversion

2.1. Compounding: the process of combining two words (free morphemes) to create a new word (commonly a noun, verb, or adjective).

2.1.1. An example: football = foot + ball

2.2. Derivation: the origin of something, such as a word, from which another form has developed, or the new form itself.

2.2.1. An example: Sing -> singer

2.3. Inflection: a change in the form of a word (typically the ending) to express a grammatical function or attribute such as tense, mood, person, number, case, and gender.

2.3.1. Examples: cats, does, walked, sleeping…

2.4. Conversion: a word-formation process that assigns an existing word to a different word class, part of speech, or syntactic category.

2.4.1. An example: bottle (garrafa) / to bottle (engarrafar)

3. Word Classes

3.1. Parts of speech: nouns, verbs, adjectives and adverbs.