Language Difficulty for English Speakers
How long will it take to become proficient in a foreign language?
People often ask: "How long will it take me to become proficient in language X?" This question is impossible to answer because a lot depends on a person's language learning ability, motivation, learning environment, intensity of instruction, and prior experience in learning foreign languages. Last, but not least, it depends on the level of proficiency the person wishes to attain.
Different language skills
There is no such thing as across-the-board proficiency in a particular language. Proficiency is usually measured in terms of four skills:
Learners usually have different levels of proficiency in the four skills. Consequently, the four skills cannot be assessed by one test. Each one requires an independent evaluation.
Levels of proficiency
Two widely used guidelines identify stages of proficiency, as opposed to achievement. Both guidelines represent a hierarchy of global characterizations of integrated performance in speaking, listening, reading and writing. Each description is a representative sample of a particular range of ability, and each level subsumes all previous levels, moving from simple to complex.
It is important to understand that these guidelines are not intended to measure what an individual has achieved through specific classroom instruction but rather to allow assessment of what an individual can and cannot do, regardless of where, when, or how the language has been acquired.
ACTFL (American Council of Teachers of Foreign Languages) has guidelines for speaking (1999) and preliminary guidelines for writing. The ILR (US Government Interagency Language Roundtable) has guidelines for speaking, reading, listening, writing and translation.
The two sets of guidelines for speaking only are given side-by-side below. Note that the ACTFL scale goes up only to the Superior level, while the ILR scale includes Advanced Professional Proficiency and Functionally Native Proficiency. ...more
World Languages is a commercial site but also a one-stop information website "dedicated to the world’s most important and populous languages... and language-related IT,"
OK so it's not about learning English, per se, but information about languages in general and learning languages does relate.
In particular, the chart for assessing different language skills and levels of proficiency seems adaptable to skills and levels in others languages.
Also a source about individual world languages, language families, fascinating language factoids (which always made language learning more interesting for me)