Final answer:
The nasal cannula is the most common oxygen delivery system that allows for unobstructed eating and speaking, due to its design of two prongs inserted into the nostrils.
Step-by-step explanation:
The oxygen delivery system most commonly used that does not impede eating or speaking is the nasal cannula. A nasal cannula consists of two small prongs that are inserted into the nostrils and is connected by tubing to an oxygen supply. Because the mouth remains uncovered, this allows individuals to eat and speak without obstruction, contrasting with other devices such as the oxygen hood, mask, or tent which can interfere with these activities.
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