Basic Terms in linguistics

Prescriptive grammar:  The grammar that we are taught in school.  Typically a prescriptive grammar is about the "shoulds and shouldn'ts" in a language rather than a description of what speakers actually know when they know a language.  Prescriptive grammars typically reflect the grammar of a written standard and are concerned with making determinations about the "correct" choice when there are potential variants (e.g. in English, we can choose to either separate a preposition from the noun it modifies [What did you play with?] or not to do so [With what did you play]).  The prescriptive grammar of English says that only one of those is "correct" even though all speakers of English have the option.

Standard language:  The variety of a language that serves as the model for what is "correct" and "incorrect" for a given language.  The standard language is generally the one that is written.

Dialect:  A variety of a language with a grammar that differs in predictable ways from other varieties of the language.  In many places, “dialects” are especially tied to different regions or geographic areas.

Generative grammar:  The idea that a finite set of rules or constraints can generate [e.g. produce as an output] an infinite number of utterances, many of them novel.  This model shows that native speakers of a language acquire a set of rules and a lexicon rather than specific sentences.

Phonetics: The study of the sounds we use to produce/interpret speech.

Phonology: The study of the sounds that occur in specific languages and the rules or constraints that govern when they occur.

Morphology:  The study of the units of meaning (words, prefixes etc.) in a language and their patterns of occurrence.

Lexicon: The set of morphemes in a language.

Root: The main meaning morpheme in a word and the morpheme to which affixes attach (e.g. in 'untie', the root is 'tie').

Inflection: The morphology that governs grammatical relationships between words (e.g. the 3rd person, present verb marker in English [-s] tells us something about the relationship between the noun and the verb).

Derivation: The morphology that governs how new meanings are created (e.g. if I attach the prefix 'un-' to a verb like 'tie', I create a new meaning--namely the opposite of the original word).

Syntax: The study of the construction of sentences in a language.  This includes the linear order (e.g. Subject Verb Object vs. Subject Object Verb) as well as the relationships between the parts of the sentence.

Semantics: The study of meaning (e.g. what does "open" mean).

Pragmatics: The study of meaning in context (e.g. "the door is open" can have different interpretations depending on the context).

Diachronic:  The study of language across time (e.g. the history of the changes in a language).

Synchronic:  The study of language at a specific point in time.

Pidgin: A language that often has a simplified grammar and lexicon and that is used as a kind of lingua franca among speakers who don't share a native language.  Pidgins are typically not anyone's native language.

Creole: A pidgin that has been expanded to fulfill all the functions of a human language and that has become some group of speakers' native language.  Of some potential confusion is the fact that creoles are often called pidgins by their speakers.