Lyfjaróbótinn er við lyfjaskápinn.

Because Icelandic uses compounds very freely. What English often writes as two words, Icelandic often writes as one.

Here, lyfjaróbótinn is built from:

• lyfja- = medicine / of medicines
• róbóti = robot
• -inn = the

So the dictionary form is lyfjaróbóti, and lyfjaróbótinn means the medicine robot.

In many Icelandic compounds, the first noun appears in a genitive form rather than its basic dictionary form.

The basic noun is lyf = medicine, drug.
Its genitive plural form is lyfja = of medicines.

That is why you get:

• lyfjaskápur = medicine cabinet
• lyfjaróbóti = medicine robot

This is a very common Icelandic pattern, but not every compound works the same way, so it is something you gradually get used to.

-inn is the suffixed definite article, meaning the.

Instead of putting a separate word before the noun, Icelandic usually attaches the definite article to the end of the noun.

So:

• lyfjaróbóti = a medicine robot
• lyfjaróbótinn = the medicine robot

And:

• lyfjaskápur = a medicine cabinet
• lyfjaskápinn = the medicine cabinet

This is one of the most important differences from English.

Er is the present tense, 3rd person singular form of vera = to be.

So here it means is.

• ég er = I am
• þú ert = you are
• hann / hún / það er = he / she / it is

Because lyfjaróbótinn is singular, Icelandic uses er.

Here við means by, next to, or at.

So við lyfjaskápinn means the robot is located by the medicine cabinet.

Be careful: við can mean different things in other contexts, such as with, against, or toward, depending on the sentence. In this sentence, it is a location word.

Because við and í mean different things.

• við lyfjaskápinn = by / next to the medicine cabinet
• í lyfjaskápnum = in / inside the medicine cabinet

So this sentence says the robot is near the cabinet, not inside it.

Because lyfjaskápinn is accusative, while lyfjaskápurinn is nominative.

The noun is:

• lyfjaskápur = medicine cabinet

Its definite forms include:

• lyfjaskápurinn = the medicine cabinet
  nominative singular
• lyfjaskápinn = the medicine cabinet
  accusative singular

After the preposition við, Icelandic uses the accusative, so the sentence needs lyfjaskápinn.

No. In this case, it does not imply movement.

That is an easy mistake for English speakers, especially if they know languages where case changes depending on movement vs. location.

With við, Icelandic normally uses the accusative even for a fixed location. So:

• er við lyfjaskápinn = is by the medicine cabinet

This sentence simply describes where the robot is.

They are in different cases because they have different jobs in the sentence.

• Lyfjaróbótinn is the subject, so it is in the nominative
• lyfjaskápinn comes after the preposition við, so it is in the accusative

So the sentence structure is:

• Lyfjaróbótinn = subject
• er = verb
• við lyfjaskápinn = place expression

This is a very normal Icelandic sentence pattern:

• subject + verb + place phrase

So:

• Lyfjaróbótinn = subject
• er = is
• við lyfjaskápinn = by the medicine cabinet

Nothing unusual is happening here. It is a straightforward declarative sentence and a good basic model to learn from.