How can we express the perception of Ralph's speech as a quality?

The phrase "was considered to be" effectively conveys the perception of Ralph's speech as a quality. This choice emphasizes the subjective nature of how Ralph's speech is viewed by others. "Considered" suggests that there is an opinion or belief about the speech, indicating an evaluation based on individual or collective judgment.

This phrasing allows for a degree of interpretation, reflecting how different people may perceive Ralph's speech differently, which is often the case with subjective qualities like eloquence or persuasive power.

The other options, while somewhat similar in meaning, don’t quite capture the nuance as effectively. For instance, "was evaluated to be" implies a more formal assessment, typically focusing on criteria or standards rather than perception. "Was regarded to be" and "was deemed to be" are also more judgmental perspectives that suggest a stronger assertion of quality rather than the open-ended nature of consideration. Thus, "was considered to be" provides the most suitable expression for the subjective perception being described.