What it is
A NATO scale, not a company requirement
ATrainP-5 is NATO's Allied Training Publication that gives participating nations a shared table for describing an individual's proficiency in a language. Its own aim clause states that it exists "to provide NATO forces with a table describing language proficiency levels" (clause 1.1), and nations adopt it for three purposes: communicating language requirements for international staff appointments, recording and reporting proficiency in international correspondence, and comparing national standards through one shared scale while preserving each nation's right to maintain its own internal proficiency standards. Nations record their agreement to use it in STANAG 6001: the Letter of Promulgation states that "the agreement of nations to use this publication is recorded in STANAG 6001." The current edition, Edition A Version 2, was promulgated in May 2016 and is effective on receipt, superseding Version 1.
Nowhere does the text name a supplier, manufacturer or other commercial role. The people actually rated against the scale are individuals, assessed by whichever training or testing arrangement their own nation runs; a company meets this only at one remove, where a role or a customer requirement specifies a result on the scale.
The six-level scale, and the plus levels
Clause 1.3 sets the scale itself: six base levels, 0 through 5, labelled No proficiency, Survival, Functional, Professional, Expert and Highly-articulate native, scored separately for each of four skills - listening, speaking, reading and writing - which Annex A describes in full for every level. This page does not reproduce those descriptions; they are the substance a rater works from directly. Annex B adds a further set of intermediate "plus" levels, 0+ through 4+, for use "for training, evaluation, recording, or reporting purposes" where ability "substantially exceeds a 0 through 4 base skill level, but does not fully or consistently meet all of the criteria for the next higher base level" (clause 1.3); a footnote to Annex B puts the same idea numerically, describing plus-level proficiency as more than halfway between two base levels.
Reporting a result
Clause 1.4 fixes the order a full profile is reported in - listening, then speaking, then reading, then writing - and clause 1.5 fixes the format itself: the four digits follow the letters SLP, for Standardized Language Profile, so that a profile such as SLP 3321 means level 3 listening, level 3 speaking, level 2 reading and level 1 writing.
What a nation can reserve
Three reservations were recorded at promulgation, and they show how much discretion a nation keeps. Belgium's own testing centre certifies levels 1 through 4 only, without using Annex B's interpolated plus values for its certificates. Canada applies the whole agreement only to members of the Canadian Forces involved in NATO affairs. Italy does not commit to the level-5 threshold that clause 1.1.a) would otherwise carry for certain international appointments. The document names no NATO-level certification scheme anywhere: what gets assessed is an individual, by a nation's own arrangement, not an organisation by an external body.
How you get it
NATO publishes ATrainP-5 through the Standardization Document Database at no charge; the NSDD listing for ATrainP-5 is the source. ComplyTrain does not sell it or host a copy.