Simplified Technical English (STE)

Introduction
Simplified technical English (STE), also sometimes called simplified English, is a type of controlled language typically used in the aerospace industry. It is a rules-based specification for writing clear procedures that includes a dictionary or approved terms to reduce ambiguity. ASD-STE100 is an international specification for the preparation of technical documentation. The STE specification is owned by ASD (Aerospace and Defense Industries) Brussels, Belgium. STE can be helpful when developing procedural documentation for multiple audiences.

History
First attempts towards an STE specification were made as early as the 1930s and 1970s with Basic English and Caterpillar Fundamental English.

In 1979 aerospace documentation was written in American English (Boeing, Douglas, Lockheed, etc.), in British English (Hawker Siddeley, British Aircraft Corporation, etc.) and by companies whose native language was not English (Fokker, Aeritalia, Aerospatiale, and some of the companies that formed Airbus at the time). There were also European airlines that had to translate parts of their maintenance documentation into other languages for their local mechanics.

This led the European Airline industry to approach AECMA (European Association of Aerospace Industries) to ask manufacturers to investigate the possibility of using a controlled form of English. In 1983, after an investigation into the different types of controlled languages that existed in other industries, the AECMA decided to produce its own controlled English. The AIA (Aerospace Industries Association of America) was also invited to participate in this development.

The result of this collaborative work was a guide, known as the AECMA Simplified English Guide. After a merger of AECMA with two other associations to form ASD in 2004, the specification changed its name to become ASD Simplified Technical English, Specification ASD-STE100.

Objectives of STE
STE is applied to documentation that must be easily understood by several different audiences over different topics and in many countries. Complex technical documentation can be hard to comprehend and misunderstandings can lead to accidents. It has been found that STE significantly improves the comprehensibility of more complex documents. STE works better with languages like Spanish over languages similar to Chinese or Japanese. Translating tables from English into Asian languages that use characters is difficult due to spacing and alignment on a page.

Writing Rules

This simplified form of English restricts vocabulary, verb forms, noun clusters to 3 nouns, and sentence length to 20 words for procedures. Each word has one meaning, and synonyms and jargon are not used. Sentences are kept as short, positive, and direct as possible.

No “-ing” forms of verbs are allowed. For example, “writing” is not allowed, but “to write” is allowed.

Tools
Boeing has developed a Simplified English Checker to assist during development. The linguistically-based checker uses a sophisticated 350-rule English grammar and parser, which is augmented with special functions that check for violations of the Simplified English standard.

HyperSTE is a plugin tool offered by Etteplan to check content for adherence to the rules and grammar of the specification.

The ASD-STE100 Dictionary specifies permitted words and texts. Issue 7 of the ASD-STE100 specification was released in January 2017 and is available for download in PDF on their website http://www.asd-ste100.org/. This PDF is updated every 3 years. The following table is an extract from a page of the ASD-STE100 Dictionary:

An explanation of the four columns:


 * Keyword (part of speech): This keyword has information on the type of word. Every permitted word in STE is only permitted as a specific word type. For example, “test” is only permitted as a noun (the test) but not as a verb (to test).
 * Approved meaning/ALTERNATIVES: This contains the definition of the permitted word. In the example table, ACCESS and ACCIDENT are allowed. Rephrasing or alternatives that are not permitted are listed in small letters (acceptance and acceptable).
 * APPROVED EXAMPLE: When the text is written in capital letters then it means that the entire text conforms to STE. If the keyword shown in column 1 is not permitted, then sample sentences in column 3 are provided with the alternatives listed in column 2.
 * Not approved: Small letters in this column indicate sentences that do not conform to STE. Column 4 will remain empty is the case of words that do conform to STE.
 * APPROVED EXAMPLE: When the text is written in capital letters then it means that the entire text conforms to STE. If the keyword shown in column 1 is not permitted, then sample sentences in column 3 are provided with the alternatives listed in column 2.
 * Not approved: Small letters in this column indicate sentences that do not conform to STE. Column 4 will remain empty is the case of words that do conform to STE.
 * Not approved: Small letters in this column indicate sentences that do not conform to STE. Column 4 will remain empty is the case of words that do conform to STE.