Learn Icelandic: Herbergisþjónustan kemur eftir tvo klukkutíma.

It is a compound noun combining herbergi (room) and þjónusta (service). In Icelandic, the first word in a compound noun is often put into the genitive (possessive) case to link them. The genitive of the strong neuter noun herbergi is herbergis, creating herbergisþjónusta (literally 'room's service'). The definite article -n is then added to the end for 'the'.

What about the compound word klukkutíma? Why doesn't it have a linking -s?

Klukkutími (hour) is formed from klukka (clock) and tími (time). Unlike strong nouns that often take an -s or -ar genitive ending, weak feminine nouns like klukka typically use their oblique form as the linking stem. The accusative, dative, and genitive form of klukka is just klukku, so they simply attach together without an extra consonant.

Why is it tvo klukkutíma instead of the nominative tveir klukkutímar?

The preposition eftir takes the accusative case when it is used to talk about time, meaning 'in' or 'after' a certain duration. Because klukkutími is a masculine noun, the number two must change to the masculine accusative tvo, and the noun takes its accusative plural form, klukkutíma.

The English translation says 'will arrive', but kemur means 'comes'. Why is the present tense used here?