Как уже отметили выше, этих градаций может быть стопятьсот.
Скажем, два самых популярных теста, которые вроде как имеют значимость не просто для форумных посиделок, а предоставляют возможность учиться на английском, важны для иммиграции и т.п.:
TOEFL
Reading Skills: High - Intermediate - Low
Speaking Skills: Good - Fair - Limited - Weak
Listening Skills: High - Intermediate - Low
Writing Skills: Good - Fair - Limited - Zero
IELTS
The IELTS 9-band scale. Each band corresponds to a level of English competence. All parts of the test and the Overall Band Score can be reported in whole and half bands, eg 6.5, 7.0, 7.5, 8.0.
Band 9: Expert user: has fully operational command of the language: appropriate, accurate and fluent with complete understanding.
Band 8: Very good user: has fully operational command of the language with only occasional unsystematic inaccuracies and inappropriacies. Misunderstandings may occur in unfamiliar situations. Handles complex detailed argumentation well.
Band 7: Good user: has operational command of the language, though with occasional inaccuracies, inappropriacies and misunderstandings in some situations. Generally handles complex language well and understands detailed reasoning.
Band 6: Competent user: has generally effective command of the language despite some inaccuracies, inappropriacies and misunderstandings. Can use and understand fairly complex language, particularly in familiar situations.
Band 5: Modest user: has partial command of the language, coping with overall meaning in most situations, though is likely to make many mistakes. Should be able to handle basic communication in own field.
Band 4: Limited user: basic competence is limited to familiar situations. Has frequent problems in understanding and expression. Is not able to use complex language.
Band 3: Extremely limited user: conveys and understands only general meaning in very familiar situations. Frequent breakdowns in communication occur.
Band 2: Intermittent user: no real communication is possible except for the most basic information using isolated words or short formulae in familiar situations and to meet immediate needs. Has great difficulty understanding spoken and written English.
Band 1: Non-user: essentially has no ability to use the language beyond possibly a few isolated words.
Но все эти градации, как и сами тесты, не имеют практически никакого отношения к реальному владению индивидуумом иностранным языком. Поскольку TOEFL сдавать недавно доводилось, могу определенно сказать, что он связан прежде всего с оценкой общего интеллекта, а язык там достаточно вторичен. Убежден, что значительное количество "native speakers" набрало бы более чем скромные баллы. Но от этого они не перестали быть "native speakers" хотя бы по праву рождения, а я со своим баллом, конечно, могу надувать щеки, но имхо даже близко не стал "fluent". Ну а если общепринятые профтесты не способны корректно классифицировать гомо сапиенс по признаку владения языком, к чему эти пустые звучные дефиниции ?