Final answer:
The best conjunction to complete the sentence is 'pero', which means 'but' or 'however' in English.
Step-by-step explanation:
The sentence 'Yo hablo español no hablo inglés' means 'I speak Spanish I don't speak English'.
The best conjunction to complete the sentence is pero, which means 'but' or 'however' in English. The use of 'pero' here indicates a contrast between speaking Spanish and not speaking English.
Learn more about Spanish conjunctions