It's important to note that "most" can be interpreted in different ways:
* Native speakers: Mandarin Chinese has the highest number of native speakers, with over 939 million people.
* Total speakers: When including second language speakers, English has more total speakers than Mandarin Chinese. However, this is a debated topic as many consider the English language to be comprised of various dialects and accents making it difficult to define a single "English" language.
So, while Mandarin Chinese has the most native speakers, depending on how you measure "most", English might have more overall speakers.