What is the purpose of "то" in a "Если ..., то" construction?

Question

I used a machine translator (DeepL, specifically) to translate the following sentence:

If I have breakfast, I usually have it before noon.

It gave me:

Если я завтракаю, то обычно я завтракаю до полудня.

What part of speech does the то represent in that sentence and what is the purpose of it? If I were to use the following instead:

Если я завтракаю, обычно я завтракаю до полудня.

Would that still be considered good Russian? Does the presence of то alter the meaning of the sentence in any way?

I have done a little research on this, but not much. In the process, I did come across this discussion thread:

если,... то...

but it still leaves some questions for me such as

1. What part of speech is it in such constructions?
2. Would my sentence still be correct without it?
3. How does the presence of "то" alter the meaning?

According a Senior Member of WordReference from Saint Petersburg (taken from the previously mentioned discussion thread):

Generally speaking, то stresses the logical connection between the two parts of the sentence, so the longer and more complex the sentence, the better it will look with this particle. It also disambiguates such cases ...

I guess I fail to see how

If I have breakfast, I usually have it before noon.

needs a logical connection or disambiguation.

Answer 1

1. What part of speech is it in such constructions?

Если... то is classified in Russian as "двойной союз" (literally "double conjunction", "two-part conjunction"), though some often call it a "составной союз" (compound conjunction), though it is debatable whether or not it is or should be counted as such.

In English terminology, it would be a correlative, being an almost complete semantic double of if—then.

3. How does the presence of "то" alter the meaning?

The difference with simple conjunction если is subtle, but it does exist.

Если A, B. and B, если A.

Here we deal with a conditional phrase: the dependent clause A acts as a condition for the independent clause B.

Если A, то B.

Here we either have a cause-and-effect relation or a condition-and-effect relation. Those are two different types of relations (cause produces the effect, while condition facilitates it). By adding that то, we transform a simple condition into a logically stronger relation.

As the quote you supplied mentions, if you have a particularly long sentence, you might want to use то in order to make the connection between the two clauses clearer, more pronounced.

2. Would my sentence still be correct without it?

Could you drop то in your example? Yes and no.

Yes, because it would work perfectly fine and convey the meaning pretty much exactly as it was in English.

No, because the way the algorithm translated the rest of your sentence will sound a bit weird without a stronger, more pronounced sentence structure то facilitates.

I am specifically referring to the fact that, for some reason, DeepL decided to do away with the pronoun you had and replaced it with the repeat of its antecedent. My guess is—it couldn't handle the existence of a single-word verb in place of to have breakfast

Basically, your sentence translated to:

If I have breakfast, then I usually have breakfast before noon.

And if you drop то it will sound a bit off in English and (personally) more so in Russian:

If I have breakfast, I usually have breakfast before noon.

So the actual translation you would probably want is:

Если я завтракаю, я обычно делаю это до полудня.

Here I replaced the repeat of завтракать with a verb-pronoun combination делать это, which roughly correlates here with to do so.

P.S. I wish to mention something that bothers me about both your English version and its translation: I desperately want it to be If I do have breakfast, I have it before noon, translating to Если я вообще завтракаю, я делаю это до полудня.

Answer 2

It's an adverb. "Если - то" is just like "If - then". You may drop "то", but the phase would lose some of its completeness.