Palm-oil is often used as a cooking oil in various African cultures. It is high in unsaturated fats and vitamins. Today it is used in a lot of processed foods. The taste of Palm-oil is very good, adding both flavor to the food as well as the nutrients.
The idea that proverbs are the cooking oil of speech shows the importance of being able to speak well in the Igbo society. Food can be cooked without cooking oil, but the meal may lack flavor and be more difficult to make. Cooking oil is extremely important to cooking as it stops the food from burning as well as adding some flavor depending on the oil used. In the same way, proverbs allow the speaker to put meaning and purpose into the conversation. Although proverbs are not necessarily "essential" to conversation, they supplement it with meaning and beauty, just as cooking oil facilitates cooking and augments a meal with flavor. Proverbs and cooking oil create more enjoyment within their respective fields of conversation and cooking.