1. Language
(n) Human speech, and the speech of a particular people of nation.
2. Accent
(n) 1. Stress on a syllable or word, 2. A mark used in written French and other languages to show the quality of a vowel, 3. Emphasis; the accent must be on hard work, 4. The way in which words are pronounced in a particular area (a Scottish accent). 5. Music; emphasis placed on a certain note or chord.
3. Dialect
(n) A way of speaking found only in a certain area or only among a certain group of people.
4. Vernacular
(n) The ordinary spoken language of a country or district.
5. Colloquialism
(n) An example of colloquial speech (informal language).