watasi no itoko ha, karendaa wo minagara tugi no syukuzitu no yotei wo kimemasu.

は marks 私のいとこ as the topic of the sentence: As for my cousin, ...

So the sentence is presenting information about the cousin:

• 私のいとこは、...決めます。
• As for my cousin, ... decides ...

If you used が, it would sound more like you are identifying who does the action:

• 私のいとこが決めます。 = My cousin is the one who decides.

In this sentence, は is the more natural choice because the cousin is simply the topic being talked about.

私のいとこ means my cousin.

Japanese いとこ does not tell you gender by itself. It can mean:

• male cousin
• female cousin

Also, unlike English, it does not tell you whether the cousin is on your mother’s side or father’s side.

So 私のいとこ is simply my cousin, with no gender specified.

の often links nouns together, similar to:

• 's
• of
• sometimes just a noun modifier in English

In this sentence:

• 私のいとこ = my cousin
• 次の祝日 = the next holiday
• 祝日の予定 = plans/schedule for the holiday

So の is connecting nouns step by step.

You can think of 次の祝日の予定 as building up from the end:

1. 予定 = plans / schedule
2. 祝日の予定 = holiday plans
3. 次の祝日の予定 = plans for the next holiday

This kind of noun stacking is very common in Japanese.

Yes, there are two を particles, and each marks a direct object of a different verb-like element.

1. カレンダーを見ながら

   • カレンダー is the object of 見る
   • while looking at the calendar

2. 次の祝日の予定を決めます

   • 予定 is the object of 決めます
   • decide the plans

So the sentence contains:

• one action in the ながら phrase: looking at the calendar
• one main action: deciding the plans

That is why two を particles appear.

見ながら means while looking.

It comes from:

• dictionary form: 見る
• stem: 見
• ながら attached to the stem: 見ながら

Pattern:

• verb stem + ながら = while doing ...

Examples:

• 音楽を聞きながら勉強します。 = I study while listening to music.
• 歩きながら話します。 = I talk while walking.

So:

• カレンダーを見ながら = while looking at the calendar

Yes. Normally, ながら is used when the same subject does both actions.

So in this sentence, the one who:

• looks at the calendar
• decides the plans

is the same person: my cousin.

That is an important rule for ながら. If the two actions had different subjects, Japanese would usually use a different structure.

次の祝日 normally means the next/upcoming holiday.

• 次の = next
• 祝日 = public holiday / national holiday

So it means the holiday that comes next on the calendar, not the one after that.

If someone wanted to clearly say the holiday after next, they would need a different expression.

These words are related but not identical:

• 祝日（しゅくじつ） = a public/national holiday
• 休日（きゅうじつ） = a day off / holiday / non-working day

So 祝日 is more specific. It refers to official holidays on the calendar, such as national holidays.

That matches the sentence well because the cousin is looking at a calendar and deciding plans for the next public holiday.

予定 can mean:

• plan
• plans
• schedule
• arrangement

The exact English word depends on context.

In this sentence, 次の祝日の予定 could be translated as:

• plans for the next holiday
• the schedule for the next holiday

English often chooses plans because it sounds natural here, but 予定 itself is flexible.

Japanese usually puts information in this general order:

• topic
• extra details
• object
• verb at the end

So this sentence is structured like:

• 私のいとこは = as for my cousin
• カレンダーを見ながら = while looking at the calendar
• 次の祝日の予定を = the plans for the next holiday
• 決めます = decides

Japanese is a verb-final language, so the main verb often comes at the end. That is why it feels reversed compared with English.

決めます is the polite non-past form of 決める.

It can mean:

• decides
• will decide
• decide(s), depending on context

Japanese often uses the polite -ます form in normal neutral conversation, textbook examples, and formal speech.

Compare:

• 決める = plain form
• 決めます = polite form

So this sentence is in polite style.

It can mean either, depending on context.

The Japanese non-past form can express:

• a habitual action
• a future action
• a general statement

So 決めます could mean:

• My cousin decides plans for the next holiday while looking at a calendar.
• My cousin will decide the plans for the next holiday while looking at a calendar.

Without more context, both are possible. Often the broader conversation tells you which meaning is intended.

No. Standard Japanese is usually written without spaces between words.

So this sentence would normally appear as:

私のいとこは、カレンダーを見ながら次の祝日の予定を決めます。

The spaces here are almost certainly added for learners to make the parts easier to see.

カレンダー is a loanword from English calendar, and loanwords are usually written in katakana.

Katakana is commonly used for:

• foreign loanwords
• onomatopoeia
• emphasis
• some names and technical terms

So カレンダー is the normal way to write calendar in Japanese.

Yes, very often it could.

Japanese frequently leaves out information that is clear from context. If it is already understood whose cousin it is, you might simply say:

いとこは、カレンダーを見ながら次の祝日の予定を決めます。

That would still mean My cousin decides the plans for the next holiday while looking at the calendar, if the context makes my clear.

Including 私の makes it explicit.