Problems with plain English

Although plain English helps to make text clear, plain English has the problems that follow:

Plain English is not sufficiently accurate.
Plain English is not designed for international readers.
Plain English does not minimize the cost of translation.
Plain English is not good for machine translation.

Plain English is not sufficiently accurate

Sometimes, different words have the same meaning. Sometimes, one word has many different meanings. Usually, a reader can understand the meaning from the context. Sometimes, plain English is not sufficiently accurate to make sure that the text is clear. For example, think about the following sentence: The cost of each component is significant.

Three interpretations are possible:

The cost of each component is large. (Possibly, the cost of each component is not important.)
The cost of each component is important. (Possibly, the cost of each component is small, but millions of components are necessary.)
The cost of each component is both large and important.

To make text as clear as possible, a controlled language is necessary. A controlled language specifies the grammatical structures and the words that a writer can use. One controlled language is ASD-STE100 Simplified Technical English.

Plain English is not designed for international readers

International readers are people who read English as second language.

In the UK, many immigrants do not know English very well. Guidance for Local Authorities on Translation of Publications explains that the UK government policy is to write in English, if practical (https://webarchive.nationalarchives.gov.uk/20120920020134/http://www.communities.gov.uk/publications/communities/translationguidance).

Many organizations have websites in English only. To make those websites accessible to the largest audience, organizations must use international English. Plain English is not sufficient.

Plain English is designed for people who read English as a first language. Plain English does not give guidelines about how to write for international readers. Some plain English guidelines conflict with the guidelines for international readers.

Frequently, business documents contain idioms that English people understand. For example, most English people know that 'out of the blue' means 'unexpectedly' or 'suddenly'. But, many international readers do not know English idioms. Frequently, machine translation of idioms gives incorrect translations.

Plain English does not minimize the cost of translation

One website about plain English contains the following sentences. The different verbs are not necessary. In both sentences, the verb 'give' is applicable:

The booklet gives…
The booklet sets out…

The following phrases have the same meaning:

From time to time
In some cases
Now and then
On occasion
Sometimes.

If text is translated, different terms for the same thing increase the costs of translation for the following reasons:

Sometimes, translators must ask the writers about the meaning of different terms.
Translation memory systems do not give the maximum possible benefits.

Plain English is not good for machine translation

In The Global English Style Guide, Kohl gives many guidelines about how to write for machine translation.

Plain English is not designed for machine translation. Therefore, plain English gives bad translations more frequently than text that is designed for machine translation.