Quora: “What is the easiest spoken language to learn?”

The Defense Language Institute, one of the USA's top language schools, categorizes languages into four difficulty levels based on the amount of class time they've found it takes native English-speaking students to reach a particular level of fluency.

• Category I languages, 26-week courses, include Spanish, French, Italian and Portuguese.
• Category II, 35 weeks, includes German and Indonesian
• Category III, 48 weeks, includes Dari, Persian Farsi, Russian, Uzbek, Hindi, Urdu, Hebrew, Thai, Serbian Croatian, Tagalog, Turkish, Sorani and Kurmanji
• Category IV, 64 weeks, includes Arabic, Chinese Mandarin, Korean, Japanese and Pashto

Source: DLI’s language guidelines (ausa.org) Steven Grimm

From the comments: an infographic as well! Although I doubt Romanian is really an ‘easy’ language for foreigners/English native speakers, with common words originating from Slavic languages, complicated plural forms and three genders for nouns (like in German) – neuter is actually a mixture of masculine and feminine – and enclitic definite articles.

Japanese looks very complex though – and I would still like to learn it sometime:

There is polite Japanese, plain Japanese, and then there is honourific Keigo containing 3 honourific languages. The word for 'I' has at least six different words; watashi (polite), watakushi (very polite), boku (for men only, casual), ore (men only, very casual), washi (antiquated) and chin (only used by the Emperor). simonsaysjapan