K is for ...

kew

is a powerful but small object-oriented programming language that offers many advanced features, including proper closures, first-class variables, relations, continuations, exceptions, dynamic variables, security, transactions, persistence....

It is based on ideas drawn from many contexts, including Smalltalk, Scheme, Miranda, RDF (yes, the XML thing), Java. It has a small footprint and a concise API that makes it ideal for embedding in other programs, and a powerful security model that makes it good for writing applets.

Kevo

A Forth-like concatenative prototype-based object-oriented programming language.

Key

Not satisfied by the versatility of existing programming languages, Patrick Soquet decided to develop Key, a dynamic language that allowed both class abstraction and object description. Today, after more than 10 years of language and tool development, Key is at the heart of software developed and published by Tribeworks and is used daily throughout the world to produce software for PCs, interactive terminals, and CD-ROMs.
According to Patrick Soquet, co-founder of Tribeworks, "Programming languages are not neutral. They condition application design and development. The characteristics of Key allow you to work in a manner that is entirely different from Java or C#. At a time when everyone is claiming this or that standard, it's satisfying to deliver with a truly open alternative!"

KiXtart

is a logon script processor and enhanced batch scripting language for computers running Windows XP, Windows 2000, Windows NT or Windows 9x in a Windows Networking environment.

Kogut

Kogut is an experimental programming language which supports functional and scripting-style programming, and a non-traditional flavor of object-oriented programming. Its semantics is most similar to Scheme or Dylan, but the syntax looks more like ML or Ruby.

The name "Kogut" means "Rooster" ("Cock") in Polish and is pronounced like [KOH-goot].