Learn Hardcore Russian: Учитель спокойно напоминает ему, что спешка и то, что он рассеянный, только мешают. - The teacher calmly reminds him that rushing and the fact that he is absent-minded only get in the way.

ему answers кому? – to whom (does he remind)? → dative
что спешка и то, что он рассеянный, только мешают is the thing being reminded → a что-clause

You can’t say напоминать кого in this meaning (to remind someone of something).
Instead you say:

Напомни мне, что завтра встреча. – Remind me that the meeting is tomorrow.
Она напомнила ему о встрече. – She reminded him about the meeting.

So ему is the indirect object in the dative, which is exactly what the verb requires.

Why is напоминает (imperfective present) used here and not a perfective form like напомнил or напомнит?

Aspect and tense here show how the action is viewed:

напоминает – imperfective present
- can mean a current ongoing action: is reminding
- or a characteristic / repeated action: reminds (as he usually does)
напомнил – perfective past: one completed reminder in the past
напомнит – perfective future: one completed reminder in the future

In context, Учитель спокойно напоминает ему... sounds like either:

a description of what is happening right now in a neutral way (The teacher calmly reminds him…), or
a general habit (The teacher (as a rule) calmly reminds him…).

Using напомнил would shift it to a specific completed past event: The teacher calmly reminded him (once, at that moment)…

So the imperfective present is used to describe the situation as an ongoing or typical action, not as a single finished act.

Why is the word order Учитель спокойно напоминает ему and not, for example, Учитель напоминает ему спокойно or Спокойно учитель напоминает ему?

Russian word order is flexible, but the chosen order affects rhythm and emphasis.

Учитель спокойно напоминает ему...
- neutral, natural order
- учитель = topic / subject
- спокойно directly modifies напоминает, highlighting how he reminds (calmly)
- ему is less important information, so it comes later

Alternatives are possible but sound different:

Учитель напоминает ему спокойно...
Sounds a bit unusual; спокойно is somewhat detached from the verb and can feel stylistically awkward.
Спокойно учитель напоминает ему...
Stronger emphasis on спокойно (Calmly, the teacher reminds him...), like contrasting it with some other manner (e.g., not angrily).

Native speakers normally put short adverbs of manner (спокойно, громко, тихо) right before the verb, so the original order is the most natural.

Why do we need то in то, что он рассеянный? Could we say just что он рассеянный?

то, что он рассеянный is a set construction that nominalizes the clause, roughly like “the fact that he is absent‑minded”.

то = “that / the thing / the fact”
что он рассеянный = “that he is absent‑minded” (a subordinate clause)

Together: то, что он рассеянный → a noun‑like phrase.

In the sentence, we have a coordinated subject:

спешка (haste)
(и) то, что он рассеянный (and the fact that he is absent‑minded)

For coordination, both parts need to function grammatically as “things.”

If you removed то and tried to say:

✗ спешка и что он рассеянный только мешают

this would be ungrammatical: plain что он рассеянный here does not work directly as a coordinated noun with спешка.

So то is necessary to turn the whole то, что он рассеянный into something that can stand alongside спешка as another subject.

Why does the verb мешают appear in the plural? What exactly is the subject here?

The subject is a compound one:

спешка – haste
то, что он рассеянный – the fact that he is absent‑minded

Joined by и:

спешка и то, что он рассеянный → two items together

In Russian, when the subject has two (or more) parts connected by и, the verb normally agrees in the plural:

Мама и папа пришли. – Mother and father came.
Спешка и то, что он рассеянный, только мешают. – Haste and the fact that he is absent‑minded only get in the way.

So мешают is plural to match this compound subject.

Why is рассеянный used (long form adjective) and not the short form рассеян?

Long and short adjective forms often differ in nuance:

рассеянный (long form)
- sounds more like a stable characteristic / trait
- close in feel to English "he is an absent‑minded person"
рассеян (short form)
- more like a state or condition, often temporary or situational
- like "he is distracted (right now / at the moment)"

So:

то, что он рассеянный emphasizes that being absent‑minded is one of his qualities, a regular problem that gets in the way.
то, что он рассеян would more likely be understood as “the fact that at this moment he is distracted,” which would change the nuance.

The sentence talks about general obstacles to his work or learning, so the long form рассеянный fits better.

What exactly does только modify in только мешают, and what is its effect on the meaning?

Here только is placed directly before the verb мешают, so it modifies the verb:

только мешают ≈ “(they) only interfere / do nothing but interfere”

This suggests:

These qualities (haste and absent‑mindedness) do not help in any way.
Their sole effect is negative: they just get in the way.

Compare:

только учитель напоминает ему... – Only the teacher reminds him... (только modifies учитель)
учитель только напоминает ему... – The teacher only reminds him... (and maybe doesn’t do other things)

So word order makes it clear that только is limiting the action мешают, not the teacher or the student.

Why is there a comma before что in напоминает ему, что спешка..., and why are there commas around что он рассеянный?

There are actually two different uses of что here and two different comma rules.

напоминает ему, что спешка и то, что он рассеянный, только мешают
This что introduces a subordinate content clause (“that…”).
Rule: a subordinate clause is separated from the main clause with a comma:
- Учитель напоминает ему, что…
  – The teacher reminds him that…
то, что он рассеянный,
Here что introduces a clause that explains то (“that which / the fact that…”).
This is also a subordinate clause, embedded inside the larger subordinate clause, and it is set off by commas:
- то, что он рассеянный, → the fact that he is absent‑minded

So:

First comma: separates the main clause from the “that…” clause.
Second and third commas: mark the inner clause что он рассеянный, which depends on то.

Could we say о том, что спешка и то, что он рассеянный, только мешают instead of just что спешка и то, что он рассеянный, только мешают?

Yes, grammatically you can say:

Учитель спокойно напоминает ему о том, что спешка и то, что он рассеянный, только мешают.

The difference:

напоминать кому, что...
- very common, direct: “remind someone that…”
- the что‑clause is the direct object of напоминает
напоминать кому о том, что...
- slightly more formal/explicit
- literally “remind someone about the fact that…”

Meaning-wise, they are almost identical here. The version without о том is a bit shorter and more neutral, so it’s the more typical choice in everyday language.

Why is ему not repeated after мешают? Shouldn’t it be мешают ему?

It could be repeated:

...что спешка и то, что он рассеянный, только мешают ему.

That would be completely correct and clear.

But Russian often omits repeated elements if they are obvious from context. Here the dative ему already appears right before in напоминает ему, and the natural interpretation of мешают is “hinder him,” so the listener easily supplies ему mentally.

Adding ему after мешают would:

make the sentence slightly longer,
put a bit more emphasis on to him personally.

Omitting it keeps the sentence more compact without creating ambiguity.

Could we replace то, что он рассеянный with the noun его рассеянность? Would that change the meaning?

Yes, you could say:

...что спешка и его рассеянность только мешают.

This is fully grammatical and very natural.

Nuance:

то, что он рассеянный – literally “the fact that he is absent‑minded”
- sounds a bit more explanatory or analytical
- emphasizes the statement about him
его рассеянность – “his absent‑mindedness” (a plain noun)
- more compact, more neutral stylistically
- treats absent‑mindedness as a simple, named trait

In most everyday contexts, его рассеянность would probably be preferred just for brevity. The original то, что он рассеянный puts slightly more focus on the description itself, as something the teacher is pointing out.

Why is спешка singular here? Could we say спешки in the plural?

Спешка is an abstract mass noun here, like “haste” in English:

спешка – haste, hurrying in general
used in the singular to talk about the quality/behavior as such

Saying спешки (plural) is possible but would usually imply separate concrete instances or varieties of haste in some special context, which would sound odd here.

In:

что спешка... только мешают

we are speaking about haste as a general tendency, not about multiple distinct hastes, so the singular спешка is the normal, idiomatic choice.