Learn Hardcore Indonesian: Saya mengalihkan perhatian dari ponsel ke catatan ketika pembicara mulai menjelaskan slide yang penting. - I shift my attention from my phone to my notes when the speaker begins to explain the important slides.

mengalihkan = to divert / to shift / to turn (something) aside
- root: alih (to move/shift from one place/state to another)
perhatian = attention

So mengalihkan perhatian literally means to divert/shift attention.

It is a very common collocation in Indonesian, similar to English to shift my attention or to take my mind off something. You will often see it in patterns like:

mengalihkan perhatian dari X ke Y = to shift one’s attention from X to Y
mengalihkan perhatian anak = to distract a child

Could we just use beralih instead of mengalihkan perhatian?

You can, but the nuance changes a bit.

beralih = to move / switch / shift (intransitive, focuses on the subject changing)
- Saya beralih dari ponsel ke catatan.
  = I switched from my phone to my notes.
mengalihkan perhatian = to divert attention (transitive, focuses on what you are moving: your attention)
- Saya mengalihkan perhatian dari ponsel ke catatan.
  = I shifted my attention from my phone to my notes.

Both are correct, but mengalihkan perhatian is more explicit that what is being moved is attention, not the physical person. Beralih feels a bit more compact and neutral; mengalihkan perhatian can sound slightly more careful or descriptive.

How does the dari ... ke ... structure work here?

dari ... ke ... is a very common pattern for movement or change:

dari = from
ke = to

In this sentence:

dari ponsel = from (the) phone
ke catatan = to (the) notes

So mengalihkan perhatian dari ponsel ke catatan mirrors English shift my attention from my phone to my notes.

You can use this structure with many verbs of change/movement:

pindah dari Jakarta ke Bandung = move from Jakarta to Bandung
beralih dari topik A ke topik B = shift from topic A to topic B
berubah dari merah ke biru = change from red to blue

Why is it just catatan, not catatan saya? How do I say my notes?

In Indonesian, possession is often understood from context and does not always need to be stated.

catatan literally = notes / a note / written notes
In this context, it is naturally understood as my notes.

If you want to make my notes explicit, you can say:

catatan saya = my notes
- Saya mengalihkan perhatian dari ponsel ke catatan saya ...

Both are correct. Leaving out saya is common when it’s obvious whose notes are being talked about.

Is ponsel the usual word for phone? What about HP?

Yes, ponsel is a standard, relatively neutral word for mobile phone / cell phone.

Other common options:

HP (pronounced ha-pe)
- Extremely common in everyday speech. Comes from the abbreviation handphone.
- Saya mengalihkan perhatian dari HP ke catatan ...
telepon genggam
- More formal or written; literally handheld telephone.

In casual conversation, HP is probably the most frequent. In writing, especially more neutral or formal writing, ponsel is very common and appropriate.

What is the nuance of ketika here? How is it different from saat or waktu?

All three – ketika, saat, waktu – can translate as when, but there are slight tendencies:

ketika
- Neutral, common in both spoken and written Indonesian.
- Natural for linking two events in time:
  ... ketika pembicara mulai menjelaskan ...
saat
- Very common too; often feels slightly more colloquial or flexible.
- Works fine here as well:
  ... saat pembicara mulai menjelaskan ...
waktu
- Literally time, but also used as when informally.
- Sounds a bit more casual in this kind of sentence:
  ... waktu pembicara mulai menjelaskan ...

In this sentence, ketika and saat are both very natural. waktu is acceptable in speech, but a bit more informal.

How does mulai menjelaskan work grammatically? Can I say mulai untuk menjelaskan or mulai menjelaskannya?

The pattern is:

mulai + verb = start/begin doing something

So:

mulai menjelaskan = start (to) explain / begin explaining

About your variations:

mulai untuk menjelaskan
- Grammatically possible, but usually unnecessary.
- Everyday Indonesian prefers just mulai menjelaskan.
- untuk here does not add much; it can sound a bit heavier or too formal in many contexts.
mulai menjelaskannya
- menjelaskan
  - -nya (object pronoun it/him/her/them)
- Means start explaining it.
- You would use this if what is being explained is already known from context:
  ... ketika pembicara mulai menjelaskannya. = when the speaker started explaining it.
- In your sentence, slide yang penting is mentioned explicitly right after, so you don’t need -nya.

What exactly does pembicara mean? Is it just speaker?

Yes, pembicara literally means speaker – someone who is speaking, usually in a more formal or public context (giving a talk, lecture, presentation).

Common related words:

pembicara = the speaker (the person giving the talk)
pembawa acara = host / MC
narasumber = resource person / invited expert (often in seminars, TV shows, etc.)

In a presentation or seminar context, pembicara is the usual word for the speaker.

How do we know this sentence is in the past if Indonesian has no past tense?

Indonesian generally does not change the verb form for tense. Instead, past, present, or future is understood from:

Time expressions (e.g. kemarin, tadi pagi, nanti)
Context and logic

In this sentence:

The structure ketika pembicara mulai menjelaskan slide yang penting suggests a specific event in time.
In a narrative about a talk or lecture, this will naturally be interpreted as past:
I shifted my attention ... when the speaker began to explain ...

If you really wanted to emphasize the past, you could add a time expression:

Tadi, saya mengalihkan perhatian ... = Earlier, I shifted my attention ...
Kemarin saat presentasi, saya mengalihkan perhatian ... = Yesterday during the presentation, I shifted my attention ...

What does yang do in slide yang penting?

yang introduces a descriptive clause or phrase that modifies a noun. In slide yang penting:

slide = slide
yang penting = that is important / which is important

So slide yang penting literally means the slide that is important.

In simpler terms, yang here works like that / which in English relative clauses, or it can just mark an adjective phrase that gives essential information about the noun.

Is there any difference between slide yang penting and slide penting?

They are very close in meaning, but there is a slight nuance:

slide penting
- penting is just an adjective modifying slide.
- Feels like an important slide in a more general sense.
slide yang penting
- Feels a bit more specific/definite: the slide that is important, the important slide (out of several).
- Can sound slightly more focused or emphasised.

In many real situations, they are interchangeable, and most speakers wouldn’t feel a big difference. In this sentence, slide yang penting suggests the particular important slide that the speaker is now explaining.

Can saya be dropped at the beginning? What would that sound like?

Yes, Indonesian often allows the subject pronoun to be omitted if it is clear from context.

Full:
Saya mengalihkan perhatian dari ponsel ke catatan ketika ...
Without saya:
Mengalihkan perhatian dari ponsel ke catatan ketika ...

Dropping saya:

Is common in notes, headlines, or very informal contexts (e.g. diary, to‑do style, or when it’s already obvious you are talking about yourself).
Can feel less like a full sentence and more like a fragment or instruction.

In normal narrative speech or writing, keeping saya is more natural and complete.

Is catatan singular or plural here? How does Indonesian express notes vs a note?

catatan can mean a note or notes depending on context. Indonesian usually does not mark plural on the noun itself.

catatan = note / notes
catatan kuliah = lecture notes
catatan kecil = a small note / some little notes (context decides)

If you want to emphasize plurality, you can:

Repeat the noun: catatan-catatan (sounds a bit formal or written), or
Add a quantifier: banyak catatan = many notes.

In your sentence, catatan is naturally understood as my notes (plural) in English, because that fits the real-world context (lecture notes).