In order to make judgments about the kinds of tasks a language speaker is able to perform, or to compare the abilities of different speakers, proficiency scales have been developed. These scales provide profiles of speakers at a number of levels, outlining the tasks a speaker can tackle, and the skill with which they can tackle them. Encompassing discreet areas of expertise such as fluency, vocabulary, pronunciation, and grammar, a proficiency scale provides universal criteria against which an individual’s performance can be compared.
LTI can provide reliable ratings against any of these scales.
Information on the study time it may take to reach particular levels is available here.