If using a broad definition of 'language', the fastest most understandable language used today is computer language. Written language on the internet is easily and quickly translated (though sometimes with errors).
If you mean spoken to written languages, English is the world's universal business language today.
Most experts believe immersion is the fastest way to learn any language.
most of the language is french but there is some British language there to
Chinese (Mandarin)
Bantu
The fastest production four-stroke single cylinder motorcycle is most likely the 2011 Honda CBR250R.
In 1960, the second most spoken language in the United States was Spanish.
Spanish.
Realistic language is more understandable than flowery speech or dull textbook language. Most people would rather read a book written in "plain old English" instead of reading a lot of long words and fancy terms.
The fastest computers are constantly changing. Even if I knew the answer right now, I would be wrong next week. Most the fastest computers today are designed for high performance gaming from companies such as Alienware.
The majority of Latin Americans in the Western Hemisphere speak Spanish as their first language.
Iran
Most Europeans today speak Indo-European languages, which include language families like Germanic, Romance, and Slavic. These are the most widespread language groups across Europe.