Ég vökva pottaplöntuna í gluggakistunni á morgnana.

In Icelandic, the 1st person singular present tense of many verbs is often identical to the infinitive.

So:

• infinitive: að vökva = to water
• present: ég vökva = I water

Compare other present-tense forms:

• ég vökva
• þú vökvar
• hann/hún/það vökvar

So even though vökva can mean to water in a dictionary, after ég it is understood as I water.

Because it is a definite direct object.

The verb vökva takes the accusative case, so the potted plant has to be in the accusative. The base noun is pottaplanta. In the accusative singular, that becomes pottaplöntu. Then the suffixed definite article -na is added:

• pottaplanta = a potted plant
• pottaplöntu = a potted plant, accusative singular
• pottaplöntuna = the potted plant, accusative singular

So -una here is really the accusative form plus the attached the.

This is a normal vowel change in Icelandic called u-umlaut.

The noun planta changes in some forms because of the ending:

• nominative singular: planta
• accusative singular: plöntu

The a changes to ö when a following ending contains u. So when the object form is needed, planta becomes plöntu, and then with the definite article you get plöntuna.

This kind of stem change is very common in Icelandic noun declension.

Yes. Pottaplanta is a compound noun.

It is made from:

• pottur = pot
• planta = plant

Together, pottaplanta means something like potted plant or houseplant.

Icelandic uses compound words very freely, much more than English often does. So instead of a separate phrase like plant in a pot, Icelandic can package the idea into one noun.

Because í can take two different cases, depending on meaning:

• accusative for movement into something
• dative for location in something

Here the plant is located on/in the windowsill, not moving there, so Icelandic uses the dative:

• í gluggakistunni = in/on the windowsill

That is why the noun appears in a dative form.

Because prepositions do not match perfectly from one language to another.

English usually says on the windowsill, but Icelandic commonly says í gluggakistunni. Icelandic treats gluggakista as more like a recessed or bounded space, so í is natural.

So the important lesson is:

• do not translate prepositions word-for-word
• learn the natural Icelandic expression as a whole

That ending shows two things at once:

1. the noun is definite = the windowsill
2. it is in the dative singular

The basic noun is gluggakista. In this sentence, after í with a location meaning, it has to be dative singular definite:

• gluggakista = windowsill
• gluggakistu = windowsill, dative singular indefinite
• gluggakistunni = the windowsill, dative singular definite

Again, Icelandic usually puts the at the end of the noun rather than using a separate word.

Because Icelandic often uses the plural for habitual time expressions like in the mornings.

So:

• á morgnana = in the mornings / every morning / mornings

The noun behind it is morgunn = morning. In this expression, Icelandic uses the accusative plural definite form.

This is very natural Icelandic for something that happens regularly, not just once.

No. This is a very common thing for learners to mix up.

• á morgun = tomorrow
• á morgnana = in the mornings / every morning

So the -na ending makes a big difference here. In your sentence, the meaning is habitual: the action happens in the mornings generally.

Yes. Icelandic word order is more flexible than English word order, but it still follows important patterns, especially verb-second order in main clauses.

The sentence as given is perfectly natural:

• Ég vökva pottaplöntuna í gluggakistunni á morgnana.

But you could also front the time phrase:

• Á morgnana vökva ég pottaplöntuna í gluggakistunni.

Notice what happens: when Á morgnana moves to the front, the verb vökva still stays in the second position, and ég moves after it.

That is a key Icelandic sentence pattern.

Because Icelandic usually expresses the by attaching it to the noun as a suffix.

In this sentence:

• pottaplöntuna = the potted plant
• gluggakistunni = the windowsill

This is one of the biggest differences from English. Instead of a separate article before the noun, Icelandic often builds definiteness directly into the noun form itself.

So when learning Icelandic nouns, it is important to learn not just the base word, but also how it changes with:

• case
• number
• definiteness