Answer:
"I do not prefer to talk" is grammatically better than "I prefer to do not talk."
Explanation:
The best way to say this is "I prefer not to talk"
"I do not prefer to talk" is grammatically correct but not commonly used. This statement may be used when one is asked (directly or indirectly) whether he/she prefers to talk or not. Saying "I do not prefer to talk" does not convey clearly what you really prefer.
"I prefer not to talk" conveys the message better. It also informs the audience what your preference is. Using negative of prefer is not common There may be <em>like</em> or do not like, but negative of some words like <em>suggest, advise, prefer, request</em> are ambiguous.
For example, "I advise not to talk" is better in conveying the sense than "I do not advise to talk" (because it does not tell what you really advise).
Yes it is a full sentence
