What is the easiest language to learn?
English is the easiest language to learn, no question about that
Easy is a relative term, it depends on our native language.
However, what more than makes up for differences in grammar and vocabulary is the quantity and quality of content on the Internet. The quantity and quality of free English content on the Internet is unmatched.
English is the easiest language to master in the world!
I am not just saying it, I truly believe it.
Availability of some amazing quality information on every conceivable topic coupled with the best monolingual learner’s dictionaries and all that free of charge, in your pocket, make English the easiest language to learn/master
Which is the most difficult language to master?
What makes a language easy or difficult to learn/master is:
the availability, or lack thereof, of interesting content and good monolingual learner’s dictionaries.
There is simply no excuse for not being able to speak English, no excuse whatsoever
Read and Listen to interesting content and use monolingual learner’s dictionaries, and I suggest you start with my book Virtually Native.