Taking the perspective that software architecture is the software infrastructure within which application functionality is deployed Conference Paper What is Software Architecture
, I would recommend AO-ADL (the Aspect-Oriented Architecture Description Language) from Monica Pinto, Lidia Fuentes et al (see, for example
Article Specifying aspect-oriented architectures in AO-ADL
). Aspects provide the semtantics specify architectural tactics/strategies and architectural responsibilities as cross-cutting concerns.
I have experience with several software architecture documentation models (from formal to informal). Choosing a documentation model, and the required architectural views, depends on the kind of project your are working on. My advice is to make sure you consider these views: static (that show how the system is decomposed), dynamic (that show the system behavior at run time) and allocation (that shows where the system is deployed/installed). Recently I found the C4 model propose by Simon Brown (see: https://leanpub.com/b/software-architecture). I really like it; it considers the above mentioned views. I hope it helps.