Kind of, Sort of, and Type ofHow to use "kind of," "sort of," and "type of" correctly
The expressions kind of, sort of, and type of are essentially interchangeable:
a certain kind of person = a certain sort of person = a certain type of person
Remember not to add an article (a or an) at the end of this expression:
a kind of a person
a kind of person
Remember to keep number consistent in phrases using these expressions:
this kind of environments these kind of environments
this kind of environment (all singular)
these kinds of environments (all plural)
This rule has not always been followed, and the usage “these kind of [noun]s” has a long, well-established history. However, this usage is now generally considered nonstandard.
The use of kind of and sort of as an adverb meaning somewhat (“kind of cool”) is considered slang. However, you only need to avoid this usage in formal writing.
Common Errors in English Usage: Errors in diction and idiom commonly made by native speakers of English
List of Common Errors in English Usage (PDF): Printable version of the complete list
Common Grammar Errors: A list of common errors in grammar (topics like subject-verb agreement and parallelism) as distinct from usage