Quora Answer: Which are the alternatives to UML?
There is human readable UML. See TextUML Toolkit
Also I have done research into Domain Specific Languages for Systems Design. You can see some of this work at Kent Palmer’s Resume. There is a tutorial there based on a paper I gave at CSER 2011 called Reworking the Integral System Engineering Method Domain Specific Languages. There is also a critique of SysML and UML at A Critique of SysML from the point of view of General Schemas Theory submitted to CSER 2005