I sometimes feel that sentences written as you speak are not easier to read than those written in other ways. In addition to that, in the case of the Japanese language, the ending of each sentence tends to become very monotonous with “desu” or “masu.” I suppose that “Write as you speak.” is not always a good recommendation. I wonder if these things apply to other languages.
Errata
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“Write as you speak.” is not always a good recommendation.
Read:
“Write as you speak” is not always a good recommendation.
My advice to language learners is to “write as you speak and speak as you write”. In this way your spoken language is not too informal, and you do not freeze when you have to write. This was my golden rule with Japanese. My Japanese remained “neutral” for a long time.
In this way your written and spoken forms of the language can reinforce each other.
Of course, the spoken and written forms of the language are different, and gradually as you become more confident in the use of the language, you develop distinctive styles of language for different situations. But for the beginning, and for quite a while thereafter, I have always found this rule helpful.
Both writing and formal speech can be non-colloquial. In writing, non-colloquial language is sometimes preferable and easy to read. On the other hand, in speaking we can use either colloquial or formal language. In informal conversations we can use either colloquial or “bookish” language; in formal speech we usually use non-colloquial language. I understand that your advice is not to be too colloquial in speaking, as well as not to be too “bookish” in writing.
I appreciate your advice.