Question

Yo siempre hablo el idioma local con todo el mundo.

Answer 1

Answer:

Yo nunca hablo el idioma local con nadie.

Explanation:

In this case you are using an adverb of frequency that  means always:

- Yo siempre hablo el idioma local con todo el mundo.

If you want to transform this sentence in a negative sentence you must change the adverb of frequency using the antonym never instead of always:

Yo nunca hablo el idioma local con todo el mundo.

However, It seems that the phrase "todo el mundo" is affirmative you must turn it negative. To do so, you must use a negative word like nadie.