Editing Cognate (section)

===Root and derivatives===
A '''[[root (linguistics)|root]]''' is the source of related words within a single language (no language barrier is crossed).

Similar to the distinction between ''etymon'' and ''root'', a nuanced distinction can sometimes be made between a ''descendant'' and a ''derivative''. 
 
A '''[[derivative (linguistics)|derivative]]''' is one of the words which have their source in a root word, and were at some time created from the root word using morphological constructs such as suffixes, prefixes, and slight changes to the vowels or to the consonants of the root word. 
For example ''unhappy'', ''happily'', and ''unhappily'' are all derivatives of the root word ''happy''.

The terms ''root'' and ''derivative'' are used in the analysis of morphological derivation within a language in studies that are not concerned with historical linguistics and that do not cross the language barrier.