Method and Conclusion. See here.
Results. A ratings system was designed in terms of how difficult it would be for an English-language speaker to learn the language. In the case of English, English was judged according to how hard it would be for a non-English speaker to learn the language. Speaking, reading and writing were all considered.
Ratings: Languages are rated 1-6, easiest to hardest. 1 = easiest, 2 = moderately easy to average, 3 = average to moderately difficult, 4 = very difficult, 5 = extremely difficult, 6 = most difficult of all. Ratings are impressionistic.
Time needed. Time needed for an English language speaker to learn the language “reasonably well”: Level 1 languages = 3 months-1 year. Level 2 languages = 6 months-1 year. Level 3 languages = 1-2 years. Level 4 languages = 2 years. Level 5 languages = 3-4 years, but some may take longer. Level 6 languages = more than 4 years.
This post will look at the Dônđän Wu language in terms of how difficult it would be for an English speaker to learn it.
A recent 15 year survey out of Fudan University utilizing both the departments of Linguistics and Anthropology looked at 579 different languages in 91 linguistic families in order to try to find the most complicated language in the world. The result was that a Wu language dialect (or perhaps a separate language) in the Fengxian district of southern Shanghai (Dônđän Wu) was the most phonologically complex language of all, with 20 separate vowels (Wang 2012). The nearest competitor was Norwegian with 16 vowels.
Dônđän Wu gets a 6 rating, hardest of all.
Wang, Chuan-Chao et al. 2012. Comment on ”Phonemic Diversity Supports a Serial Founder Effect Model of Language Expansion from Africa.” Science 335:657.