Final answer:
A regular language can be defined by a regular expression or a finite automaton. A Turing machine can recognize or generate any language that is recursively enumerable (RE), which includes regular and context-free languages.
Step-by-step explanation:
A regular language is a language that can be defined by a regular expression or a finite automaton. Every language that can be defined by a context-free grammar (CFG) is also a regular language. A Turing machine can recognize or generate any language that is recursively enumerable (RE), which includes both regular languages and context-free languages. Therefore, every language that can be defined by a Turing machine may or may not be defined by a context-free grammar, but it will definitely be defined by a regular expression.