From the extensive format of UML use cases to the minimal guidance of the Agile user stories, there have been many attempts to formalize the expression of software requirements. However, the free text is still the form that is used by a majority of software development organizations.
This situation was confirmed in the last Methods & Tools survey that asked the question: “How does your project manage the definition of requirements (text, user stories, models,…)?” Even if the answers were spread amongst all the proposal, the largest group of participants (27%) use only office software (word processor, spreadsheet,…) to manage their software requirements. Read the complete results and analysis on Fragmented Market for Requirements Management Tools
References
* Software Requirements Format Survey by Methods & Tools
* State of Requirements Management 2011 (PDF) by Jama Software