Learn Hardcore Finnish: Tyttö piirtää meren ja aaltoja.

Meren is the genitive singular of meri (sea). As an object, the genitive marks a “total” or completed object: the girl draws the sea (as a whole, as a complete picture).
Merta (partitive singular) would mean an ongoing or incomplete/indefinite drawing of “some sea.”
Plain meri (nominative) isn’t used here for a singular total object. With singular total objects in the affirmative, Finnish uses the genitive.

What case is aaltoja, and what does it mean here?

Aaltoja is the partitive plural of aalto (wave).
Partitive plural often means “some waves / an unspecified number of waves.”
It signals an indefinite quantity rather than “all the waves” or a specific, complete set.

Why do the two coordinated objects have different cases (meren and aaltoja)? Isn’t that inconsistent?

It’s allowed. In Finnish, each coordinated noun phrase can get the case that fits its own meaning. Here:

Meren = total object (a complete sea in the drawing).
Aaltoja = indefinite quantity (some waves). This kind of mix is normal: e.g., “Join kahvin ja vettä” = “I drank the coffee and some water.”

Could I use aallot instead of aaltoja? What’s the difference?

Aallot (nominative plural) is the plural total object: “the waves” as a whole/specific set. “Tyttö piirtää meren ja aallot” would mean she draws the sea and the (relevant/all) waves—more definite and complete.
Aaltoja stays vague: she’s drawing some waves.

Could I say merta instead of meren?

Yes, but the meaning changes:

Piirtää merta = she’s drawing (some) sea; the activity is ongoing/indefinite, not framed as a completed result.
Piirtää meren = she (will) produce a complete drawing of the sea.

Why does meri become meren? Where does the e come from?

Meri is an “old i-stem” noun. In most case forms, the final -i changes to -e- before the ending: meri → meren, mereen, meressä, merestä, merellä, etc. Compare:

Old i-stems: järvi → järven, suomi → suomen
New/loan i-stems keep the i: banaani → banaanin

How is the partitive plural of aalto formed? Why is there a j in aaltoja?

For many words ending in -o, the partitive plural takes -ja:

talo → taloja
aalto → aaltoja So the j is part of the plural partitive ending.

How is piirtää conjugated in the present, and why is it piirtää for “she draws”?

Dictionary forms are shown as the 3rd person singular present for this verb type, which matches “she/he/it draws.” Present tense:

minä piirrän
sinä piirrät
hän piirtää
me piirrämme
te piirrätte
he piirtävät Notice the gradation: rt → rr in the stem when personal endings are added (piirtää → piirrä-).

What’s the difference in meaning between present with genitive vs partitive objects (piirtää meren vs piirtää merta)?

Genitive object (meren): result-bounded/telic—framed as producing a complete drawing.
Partitive object (merta): ongoing, atelic, or partial—she’s engaged in drawing sea without implying completion. The object case carries the aspectual nuance.

Would the cases change in the negative?

Yes. Negation usually requires the partitive object:

Tyttö ei piirrä merta eikä aaltoja. (“The girl does not draw (any) sea nor (any) waves.”)

Can I use sekä instead of ja?

Ja = “and” (neutral, most common).
Sekä also means “and,” a bit more formal/literary. In pairs, it’s often sekä X että Y (“both X and Y”). You could say: Tyttö piirtää sekä meren että aaltoja.

Does Finnish need an article here? Is tyttö “the girl” or “a girl”?

Finnish has no articles. Tyttö can mean “a girl” or “the girl” depending on context. English articles are inferred from context or added by the translator.

Can I switch the order: Tyttö piirtää aaltoja ja meren?

Yes. Word order is fairly flexible. Changing the order can nudge the emphasis toward the later item. The cases still signal the meanings: aaltoja (some waves), meren (the sea as a whole).

How would I say “the waves of the sea” as one phrase?

Use a genitive attribute:

meren aallot = “the waves of the sea” (total set)
meren aaltoja = “(some) waves of the sea” (indefinite quantity) Examples as objects: Tyttö piirtää meren aallot / meren aaltoja.

Any pronunciation tips for tyttö and piirtää?

y and ö are front rounded vowels. Approximate y like French “u” in “lune,” and ö like French “eu” in “peur.”
Double letters matter: tt is a long consonant; ää is a long vowel. So:
- tyttö = TYT-to (both t’s held slightly longer)
- piirtää = PEER-tææ (fronted long “ä”)