Variation is a characteristic of language: there is more than one way of saying the same thing. Speakers may vary pronunciation (accent), word choice (lexicon), or morphology and syntax (sometimes called "grammar"). But while the diversity of variation is great, there seem to be boundaries on variation – speakers do not generally make drastic alterations in sentence word order or use novel sounds that are completely foreign to the language being spoken. Linguistic variation does not equate with language ungrammaticality, but speakers are still (often unconsciously) sensitive to what is and is not possible in their native lect.