Which verbs prefer the по-...-ски format?

Question

I have in my notes that the format по-...-ски is required over на ...-ком succeeding the verbs - говарить, читать, писать, понимать & думать.

This rule is discussed somewhat here.

However, using a search engine I found that there are varying distributions of how these are actually used. Below is a list, with the Russian form, the English translation and in brackets the percentage of that form used as returned by the search engine.

For example,

Я не говорю по-русски. - I don't speak in Russian. (70%)

This means 70% of instances were for [говорю по-русски] and 30% for [говорю на русском].

• Я не говорю по-русски. - I don't speak in Russian. (70%)
• Я скажу по-русски. - I will speak in Russian. (65%)
• Я только понимаю по-русски. - I only understand Russian. (70%)
• Я пойму по-армянски. - I will understand Armenian. (20%)
• Я читал по-английски. - I read in English. (50%)
• Я прочитаю по-испански. - I will read in English. (20%)
• Я пишу по-немецки. - I write in German. (30%)
• Я напишу по-норвежски. - I will write in Norwegian. (30%)
• Я всегда думаю по-итальянски. - I always think in Italian. (30%)

It seems the forms that should be used are "говорить", "сказать", "понимать" and, maybe, "читать". Is this correct? And what could be said of people who are using the forms like говорю на русском? Is this a mistake? A common error, or are there circumstances in which people could use говорю на русском?

Answer 1

The phrase по-русски means "in a Russian manner, the way the Russians do it".

The phrase на русском means "in Russian". Most often (but not always) it implies the word "language" (на русском языке or "in Russian language"). It is an ellipsis which has entrenched in the languages, English and Russian alike.

When used with the verbs like говорить, писать etc., the former construct literally means "to speak the Russian way, to write the Russian way" etc., and it becomes obvious from the context that "to speak the Russian way" means "to speak the Russian language".

Thus, the phrases я не говорю по-русски and я не говорю на русском (языке) mean the same and are both used in speech, although the former is more idiomatic and is used more often. Same applies to the other verbs for which "the Russian way" and "in Russian language" mean the same, like писать, читать etc.

For the verbs like понимать the literal reading is not that straightforward: "to understand the Russian way" is kinda vague. The construct понимать по-русски is a contamination of говорить по-русски and понимать русскую речь. It is an idiomatic solecism (a phrase that violates grammar or syntax). Понимать на русском is also a solecism, but it's not that idiomatic, and hence used much less frequently.

If these constructs do not imply the same noun, they are not interchangeable at all, even if the verbs are the same.

Consider these examples:

Разговаривал он на русском языке, но по-итальянски: повышая голос, жестикулируя, закатывая глаза.

Here, по-итальянски means "in the Italian way" but not "in Italian language". You cannot replace it with на итальянском.

— В следующем году будет два симпозиума: в Италии и в Китае. На каком будет лучше обсудить наше открытие? — Наше открытие будет лучше обсудить на китайском. Туда приедет больше учёных.

This is a non-idiomatic ellipsis. The noun the construct на китайском implies is not язык, so you cannot replace it with по-китайски