Ambiguity and Interpretation:
* Natural language inherently has ambiguity: Different people can interpret the same phrase differently. This can lead to different implementations of the same requirement.
* Lack of formal syntax: Structured English uses grammatical rules from natural language, which can be open to interpretation. For instance, the meaning of "if" can be different depending on context.
* No validation: Unlike formal programming languages, Structured English doesn't have a built-in mechanism for validating correctness or consistency.
Limited Expressiveness:
* Can't represent complex logic: While good for simple tasks, Structured English struggles with complex logic, especially involving nested conditions, iterations, and recursion.
* Limited data structures: It typically focuses on basic data types (numbers, strings) and struggles to represent more complex data structures (arrays, lists, etc.).
* Lack of precise control: It lacks the level of detail and precision found in programming languages, making it difficult to express fine-grained control over program flow.
Maintainability and Evolution:
* Difficulty to change: Structured English is often difficult to modify and update, especially as the complexity of the system increases.
* Limited reusability: It's less reusable compared to code written in a programming language. It's typically designed for a specific purpose and doesn't easily adapt to new scenarios.
* Less efficient than code: Structured English doesn't offer the optimization and performance advantages of compiled code.
Practical Limitations:
* Not executable: Structured English is a specification language, not an executable language. It needs to be translated into a programming language before it can be executed.
* Limited tool support: Compared to programming languages, there is limited tool support for structured English (e.g., syntax highlighting, debugging, testing).
Overall:
Structured English is a valuable tool for communication and requirements analysis, but it should be used with awareness of its limitations. When dealing with complex logic, detailed data structures, or performance-critical applications, a more formal programming language is generally preferred.