Human-human communication is critical to safe operations in air transportation systems. For example, airlines develop and train pilots to use communication protocols designed to ensure that verbally communicated air traffic clearances are correctly executed by the pilots. Given the safety criticality of such interactions, these protocols should be designed to be robust to miscommunication. However, designers may not anticipate all of the different ways that miscommunication can occur. Thus, communication protocols can fail. This paper presents a method for evaluating human-human communication protocols using the enhanced operator function model with communications, which is a task analytic modeling formalism that can be used in model-checking formal verification analyses. In particular, a novel means of generating miscommunications from normative human-human communication protocols, instantiated as enhanced operator function models with communications, is introduced. An air transportation example is used to illustrate the power of the approach, where a protocol is iteratively evaluated and improved to make it robust for multiple miscommunications. Different versions of the application protocol are used to assess the scalability of the method. Results are discussed, and avenues of future research are explored. B. Formal Methods for Human-Human Communication Behavior Although human-human communication protocols could be modeled using traditional formal methods approaches, human-human communication, which can include verbal statements, gestures, and related actions, is different from machine communication. In this context, human communications are actions [18] that occur as part of the participants' larger tasks. For analysis and engineering purposes, tasks are usually documented as part of a task analysis [19] and are designed to capture the goal-directed normative behaviors humans use to accomplish goals with The work documented here is an extended version of results originally presented at the Fifth NASA Formal Methods Symposium in May 2013 at the NASA Ames Research Center titled "Evaluating Human-Human Communication Protocols with Miscommunication Generation and Model Checking." This new paper extends the work from original proceedings by iteratively applying the described miscommunication generation technique and the EOFMC-supported formal verification analyses to multiple versions of the original protocol to improve protocol robustness. It also reports scalability benchmarks and features an expanded introduction and discussion.