William, VP of Operations, is talking via telephone with Javier, GM of the Mexico City plant, about an agreement William thought had been made several weeks ago. English is Javier's second language. What does the language difference represent that can make communication more complex?

- Filter.

Explanation:

As per the question, the language difference display 'filter' that is functioning to hinder the communication and makes it more convoluted and complex. Filters usually aim to provide the new learners(who are learning their second language) with the explanation regarding the emotional variables attached to triumph or disappointment in acquiring the second language.

In the given example, the difference in language implies that Javier as a second-language learner failed to understand the higher filters or emotional variable conveyed by William appropriately which may make him self-conscious and stressed. Therefore, the 'filter' represented in different languages(first and second language) makes the communication and acquisition of a second language more difficult and complex.