Learn Hardcore Finnish: Ensimmäinen tunti alkaa ajoissa, ja viimeinen päättyy aikaisin. - The first lesson starts on time, and the last ends early.

ajoissa means "on time / in time" relative to a planned or agreed time; it does not mean "early".
aikaisin means "early" (earlier than expected/normal, or early in the day). So alkaa ajoissa = starts on time, while alkaa aikaisin = starts earlier than usual. In the sentence, päättyy aikaisin means the last one ends earlier than normal.

Why is there a comma before bolded word ja?

In standard Finnish punctuation, you put a comma between two independent clauses, even when they’re joined by ja (and). Each clause here has its own verb and subject (the second subject is the understood tunti with viimeinen), so the comma is appropriate. If the clauses shared the same subject, you would typically omit the comma (e.g., Tunti alkaa ja päättyy myöhään).

Why is bolded word viimeinen used without repeating tunti?

Finnish often drops a repeated noun when it’s clear from context. The adjective viimeinen is "substantivized" here, so it stands for viimeinen tunti (“the last one”). This is very natural and common in Finnish.

Why present tense (alkaa, päättyy) if we’re talking about a schedule?

Finnish commonly uses the present tense for future, especially with timetables and fixed plans. Context (like a date or the nature of the sentence) tells you it’s about the future. You don’t need a separate "will" form.

What’s the difference between bolded verbs alkaa and aloittaa?

alkaa is intransitive: something begins by itself. Example: Tunti alkaa.
aloittaa is transitive: someone/something begins something. Example: Opettaja aloittaa tunnin (“The teacher starts the class”). In this sentence alkaa is correct because the class begins (no explicit starter).

Could I use bolded verb loppuu instead of päättyy?

Yes, loppua (intransitive) is also common: viimeinen loppuu aikaisin. Nuance:

päättyä is a bit more formal/neutral for events ending on schedule.
loppua is very common and can also mean “to run out” (maito loppui = the milk ran out). Both are fine here.

Why not say bolded phrase Ensimmäinen tunti on ajoissa?

You usually say olla ajoissa about people or vehicles being on schedule (Bussi on ajoissa). For events starting on time, the natural verb is alkaa: Ensimmäinen tunti alkaa ajoissa.

What’s the difference between bolded words myöhässä and myöhään (the “late” words), compared to ajoissa and aikaisin?

myöhässä = “late” relative to a schedule (the opposite of ajoissa). Example: Olen myöhässä (“I’m late”).
myöhään = “late” as a time of day (the opposite of aikaisin). Example: Menemme nukkumaan myöhään (“We go to bed late”).

Can I move the adverbs around for emphasis?

Yes. Finnish allows fronting for emphasis:

Neutral: Ensimmäinen tunti alkaa ajoissa.
Emphatic: Ajoissa alkaa ensimmäinen tunti. (puts strong focus on “on time”) Word order changes nuance, not the core meaning.

Why is there no “the” in Finnish (no articles) before “first hour” and “last (one)”?

Finnish has no articles. Definiteness is read from context, word choice (like ensimmäinen/viimeinen), and shared knowledge. Ensimmäinen tunti naturally reads as “the first hour/period”.

What case are bolded words Ensimmäinen tunti and viimeinen in?

They’re in the nominative singular because they’re subjects of their clauses. If you declined them in other cases, their stems change (since -nen adjectives change to -se- in oblique cases): ensimmäisen tunnin, viimeisen tunnin, etc.—but nominative is correct here.

Pronunciation tips for hard bits like bolded words ensimmäinen and päättyy?

Double letters are long: mm, tt, and yy are held longer.
ä is a front vowel (like the a in “cat”, but longer/clearer).
y is the front rounded vowel (like French “u” in “lune”). So päättyy has long ää, long tt, and long yy.

Is bolded word tunti “hour” or “class period”?

Literally tunti means “hour,” but in school contexts it also means a class period. If you want to be explicit, say oppitunti (“lesson/class period”).

Could I use bolded word sekä instead of ja?

You can: …, sekä viimeinen päättyy aikaisin. Sekä is more formal or list-like and often means “as well as.” With two full clauses, ja is the default; sekä is fine but slightly more formal in feel.

How do I say “earlier/earliest” if I want to compare?

Comparative adverb: aikaisemmin (also the shorter aiemmin) = “earlier.”
Superlative adverb: aikaisimmin = “earliest” (used less often in everyday speech). Example: Viimeinen päättyy aikaisemmin kuin ennen (“…earlier than before”).