Sometimes you just can't beat a good infographic. Hats off to Joe. My. God. for cluing me into this one -- "What Are the Hardest Languages to Learn?". Perhaps unsurprisingly, the US government has a breakdown of how long it thinks Foreign Service personnel should take to learn certain languages. From the Wikibooks entry:
The Foreign Service Institute (FSI) of the US Department of State has compiled approximate learning expectations for a number of languages based on the length of time it takes to achieve Speaking 3: General Professional Proficiency in Speaking (S3) and Reading 3: General Professional Proficiency in Reading (R3). The list is limited to languages taught at the Foreign Service Institute, minus languages which don't have their own Wikibook. Note that this only states the views of The Foreign Service Institute (FSI) of the US Department of State, and many language learners and experts would disagree with the ranking. It must also be kept in mind that students at FSI are almost 40 years old, are native speakers of English and have a good aptitude for formal language study, plus knowledge of several other foreign languages. They study in small classes of no more than six. Their schedule calls for 25 hours of class per week with three or four hours per day of directed self-study.The aforementioned infographic is below the fold.